Standardize how previously experimental features are handled #32620

Job	Run time
test	43m 1s
test_non_bootstrapped	0s
community_build_a	51m 13s
community_build_b	1h 25m 18s
community_build_c	51m 27s
MiMa	12m 8s
test_scala2_library_tasty	0s
test_windows_fast	49m 17s
test_sbt	19m 21s
test_windows_full	0s
build-msi-package	0s
test_java8	0s
build-sdk-package / build	8m 2s
build-chocolatey-package / build	27s
test-chocolatey-package	0s
publish_nightly	0s
publish_release	0s
nightly_documentation	0s
open_issue_on_failure	0s
	5h 20m 14s

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