Fail test with fewer than 0.5 * alloc_limit

We currently print out when the allocations are lower than the hardcoded
limit, but we don't enforce changing this. This commit adds a second
test that fails when the measured allocations are fewer than 50 % of the
ones saved in the file

perf/flame.jl

@@ -80,7 +80,9 @@ end
 
 # https://github.com/CliMA/ClimaAtmos.jl/issues/827
 @testset "Allocations limit" begin
-    @test allocs ≤ allocs_limit[job_id] * buffer
+    @test 0.5 * allocs_limit[job_id] * buffer <=
+          allocs ≤
+          allocs_limit[job_id] * buffer
 end
 
 import ClimaComms