Added setup instructions for testing the core/stdlib types. #3166

Job	Run time
windows (windows-2019, ucrt)	1m 13s
windows (windows-2019, mswin)	1m 27s
windows (windows-2022, ucrt)	58s
windows (windows-2022, mswin)	1m 41s
test (master-nightly-focal, test)	2m 11s
test (master-nightly-focal, stdlib_test)	3m 3s
test (master-nightly-focal, rubocop validate test_doc build test_generate_stdlib)	2m 38s
test (master-nightly-focal, lexer confirm_lexer)	5m 18s
test (master-nightly-focal, lexer compile)	3m 55s
test (3.2-dev-focal, test)	2m 8s
test (3.2-dev-focal, stdlib_test)	2m 51s
test (3.2-dev-focal, rubocop validate test_doc build test_generate_stdlib)	2m 24s
test (3.2-dev-focal, lexer confirm_lexer)	4m 9s
test (3.2-dev-focal, lexer compile)	3m 58s
test (3.1-dev-focal, test)	2m 34s
test (3.1-dev-focal, rubocop validate test_doc build test_generate_stdlib)	2m 23s
test (3.1-dev-focal, lexer confirm_lexer)	4m 4s
test (3.1-dev-focal, lexer compile)	4m 4s
test (3.0-dev-focal, test)	2m 17s
test (3.0-dev-focal, rubocop validate test_doc build test_generate_stdlib)	2m 26s
test (3.0-dev-focal, lexer confirm_lexer)	4m 7s
test (3.0-dev-focal, lexer compile)	4m 5s
test (2.7-dev-bionic, test)	2m 51s
test (2.7-dev-bionic, rubocop validate test_doc build test_generate_stdlib)	2m 28s
test (2.7-dev-bionic, lexer confirm_lexer)	3m 34s
test (2.7-dev-bionic, lexer compile)	3m 30s
test (2.6-bionic, test)	1m 44s
test (2.6-bionic, rubocop validate test_doc build test_generate_stdlib)	2m 11s
test (2.6-bionic, lexer confirm_lexer)	4m 6s
test (2.6-bionic, lexer compile)	4m 6s
	1h 28m 24s

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