Support IELR(1) Parser Generation #1393

Job	Run time
test-windows (head)	22m 31s
check-misc (head)	12s
steep-check (head)	13s
test-memory (head)	49m 57s
test-ruby (head, master)	6m 15s
test-ruby (3.0, master)	6m 6s
ruby-versions / Generate Ruby versions	3s
test-cpp (head, g++)	53m 5s
test-cpp (head, clang++)	51m 24s
test (2.5)	1h 15m 35s
test (2.6)	1h 26m 59s
test (2.7)	1h 26m 54s
test (3.0)	50m 29s
test (3.1)	49m 42s
test (3.2)	52m 4s
test (3.3)	55m 22s
test (head)	52m 22s
	11h 39m 13s

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