script: Fix comparison of non-ordered columns

[joamaki]

The takeColumns function assumed that the column indexes were ordered, e.g. if the table header was "Foo Bar Baz", then it'd always be referenced in order: "Foo" or "Foo Baz" but never "Baz Foo". There's no reason to assume that, so fix this and add tests.

[github-actions]

$ make test
go: downloading github.com/mitchellh/mapstructure v1.5.0
go: downloading golang.org/x/sys v0.17.0
go: downloading golang.org/x/tools v0.17.0
go: downloading github.com/fsnotify/fsnotify v1.7.0
go: downloading github.com/sagikazarmark/slog-shim v0.1.0
go: downloading github.com/spf13/afero v1.11.0
go: downloading github.com/spf13/cast v1.6.0
go: downloading github.com/subosito/gotenv v1.6.0
go: downloading github.com/hashicorp/hcl v1.0.0
go: downloading gopkg.in/ini.v1 v1.67.0
go: downloading github.com/magiconair/properties v1.8.7
go: downloading github.com/pelletier/go-toml/v2 v2.1.0
go: downloading golang.org/x/text v0.14.0
	github.com/cilium/statedb/reconciler/benchmark		coverage: 0.0% of statements
	github.com/cilium/statedb/reconciler/example		coverage: 0.0% of statements
ok  	github.com/cilium/statedb	26.069s	coverage: 82.6% of statements
ok  	github.com/cilium/statedb/index	0.005s	coverage: 28.7% of statements
ok  	github.com/cilium/statedb/internal	0.014s	coverage: 46.7% of statements
ok  	github.com/cilium/statedb/part	2.735s	coverage: 82.9% of statements
ok  	github.com/cilium/statedb/reconciler	0.355s	coverage: 88.4% of statements
-----
$ make bench
go test ./... -bench . -benchmem -test.run xxx
goos: linux
goarch: amd64
pkg: github.com/cilium/statedb
cpu: AMD EPYC 7763 64-Core Processor                
BenchmarkDB_WriteTxn_1-4                    	  448622	      2641 ns/op	    378598 objects/sec	    2816 B/op	      32 allocs/op
BenchmarkDB_WriteTxn_10-4                   	 1223732	      1002 ns/op	    997771 objects/sec	     743 B/op	      10 allocs/op
BenchmarkDB_WriteTxn_100-4                  	 1503622	       772.8 ns/op	   1293994 objects/sec	     600 B/op	       7 allocs/op
BenchmarkDB_WriteTxn_1000-4                 	 1488218	       802.8 ns/op	   1245638 objects/sec	     550 B/op	       7 allocs/op
BenchmarkDB_WriteTxn_100_SecondaryIndex-4   	  499228	      2287 ns/op	    437214 objects/sec	    1503 B/op	      37 allocs/op
BenchmarkDB_Modify-4                        	    1315	    926533 ns/op	   1079293 objects/sec	  775532 B/op	    8464 allocs/op
BenchmarkDB_GetInsert-4                     	    1221	    995599 ns/op	   1004421 objects/sec	  759304 B/op	    8463 allocs/op
BenchmarkDB_RandomInsert-4                  	    2361	    499093 ns/op	   2003635 objects/sec	  402439 B/op	    7098 allocs/op
BenchmarkDB_RandomReplace-4                 	     320	   3740781 ns/op	    267324 objects/sec	 2359132 B/op	   48574 allocs/op
BenchmarkDB_SequentialInsert-4              	    1518	    800728 ns/op	   1248864 objects/sec	  552093 B/op	    7289 allocs/op
BenchmarkDB_Changes_Baseline-4              	    1255	    943962 ns/op	   1059365 objects/sec	  553166 B/op	   10253 allocs/op
BenchmarkDB_Changes-4                       	     697	   1708319 ns/op	    585371 objects/sec	  993570 B/op	   14494 allocs/op
BenchmarkDB_RandomLookup-4                  	   22027	     54399 ns/op	  18382552 objects/sec	     160 B/op	       1 allocs/op
BenchmarkDB_SequentialLookup-4              	   27295	     44323 ns/op	  22561905 objects/sec	       0 B/op	       0 allocs/op
BenchmarkDB_Prefix_SecondaryIndex-4         	    7824	    145499 ns/op	   6872902 objects/sec	   93900 B/op	    1044 allocs/op
BenchmarkDB_FullIteration_All-4             	     979	   1260310 ns/op	  79345725 objects/sec	     480 B/op	      12 allocs/op
BenchmarkDB_FullIteration_Get-4             	     225	   5364546 ns/op	  18640947 objects/sec	       0 B/op	       0 allocs/op
BenchmarkDB_PropagationDelay-4              	  454852	      2328 ns/op	        20.00 50th_µs	        23.00 90th_µs	       102.0 99th_µs	    1590 B/op	      24 allocs/op
PASS
ok  	github.com/cilium/statedb	27.698s
PASS
ok  	github.com/cilium/statedb/index	0.003s
PASS
ok  	github.com/cilium/statedb/internal	0.003s
goos: linux
goarch: amd64
pkg: github.com/cilium/statedb/part
cpu: AMD EPYC 7763 64-Core Processor                
Benchmark_Insert_RootOnlyWatch-4    	    8971	    131963 ns/op	   7577870 objects/sec	  104167 B/op	    2041 allocs/op
Benchmark_Insert-4                  	    6165	    180833 ns/op	   5529964 objects/sec	  219070 B/op	    3065 allocs/op
Benchmark_Modify-4                  	    8226	    140058 ns/op	   7139926 objects/sec	  212502 B/op	    1205 allocs/op
Benchmark_GetInsert-4               	    6853	    171370 ns/op	   5835325 objects/sec	  212639 B/op	    1205 allocs/op
Benchmark_Replace-4                 	26961614	        44.83 ns/op	  22304026 objects/sec	       0 B/op	       0 allocs/op
Benchmark_Replace_RootOnlyWatch-4   	27158880	        44.54 ns/op	  22452950 objects/sec	       0 B/op	       0 allocs/op
Benchmark_txn_1-4                   	 3071902	       389.4 ns/op	   2568037 objects/sec	     448 B/op	       7 allocs/op
Benchmark_txn_10-4                  	 7506034	       158.0 ns/op	   6330925 objects/sec	     154 B/op	       2 allocs/op
Benchmark_txn_100-4                 	 8434983	       142.5 ns/op	   7018749 objects/sec	     224 B/op	       2 allocs/op
Benchmark_txn_1000-4                	 7403386	       161.6 ns/op	   6188126 objects/sec	     216 B/op	       2 allocs/op
Benchmark_txn_delete_1-4            	 3197378	       370.3 ns/op	   2700240 objects/sec	     856 B/op	       6 allocs/op
Benchmark_txn_delete_10-4           	 8481597	       141.2 ns/op	   7083929 objects/sec	     132 B/op	       1 allocs/op
Benchmark_txn_delete_100-4          	10441216	       114.5 ns/op	   8731049 objects/sec	      60 B/op	       1 allocs/op
Benchmark_txn_delete_1000-4         	11088364	       107.6 ns/op	   9295403 objects/sec	      26 B/op	       1 allocs/op
Benchmark_Get-4                     	   39201	     31242 ns/op	  32008700 objects/sec	       0 B/op	       0 allocs/op
Benchmark_Iterate-4                 	  177207	      6955 ns/op	 143771941 objects/sec	      80 B/op	       3 allocs/op
Benchmark_Hashmap_Insert-4          	   16006	     74845 ns/op	  13360913 objects/sec	   86556 B/op	      64 allocs/op
Benchmark_Hashmap_Get_Uint64-4      	  155406	      7744 ns/op	 129137381 objects/sec	       0 B/op	       0 allocs/op
Benchmark_Hashmap_Get_Bytes-4       	  147145	      8066 ns/op	 123974425 objects/sec	       0 B/op	       0 allocs/op
Benchmark_Uint64Map_Random-4        	    1340	    857144 ns/op	   1166665 items/sec	 2701851 B/op	    9019 allocs/op
Benchmark_Uint64Map_Sequential-4    	    1504	    790764 ns/op	   1264601 items/sec	 2492404 B/op	    9749 allocs/op
PASS
ok  	github.com/cilium/statedb/part	29.289s
PASS
ok  	github.com/cilium/statedb/reconciler	0.004s
?   	github.com/cilium/statedb/reconciler/benchmark	[no test files]
?   	github.com/cilium/statedb/reconciler/example	[no test files]
go run ./reconciler/benchmark -quiet
1000000 objects reconciled in 2.88 seconds (batch size 1000)
Throughput 347247.81 objects per second
Allocated 6011325 objects, 424761kB bytes, 515088kB bytes still in use