Dotty

Fix #21619: Refactor NotNullInfo to record every reference which is retracted once. #33556

Job	Run time
test_non_bootstrapped	0s
test_scala2_library_tasty	0s
test	53m 58s
test_windows_fast	42m 33s
test_windows_full	0s
MiMa	11m 40s
community_build_a	51m 53s
community_build_b	1h 29m 48s
community_build_c	1h 3m 28s
test_sbt	18m 29s
build-msi-package	0s
test_java8	0s
build-sdk-package / build	7m 42s
test-msi-package	0s
build-chocolatey-package / build	20s
test-chocolatey-package	0s
publish_nightly	0s
publish_release	0s
nightly_documentation	0s
open_issue_on_failure	0s
	5h 39m 51s

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