Forward-merge of lts-4.2 into lts-4.3, bringing the deprecation-warning
cleanups (#15487, #15491, #15499, #15503, #15504, #15505, #15509, #15511,
#15512, #15515, #15517, #15522) in as real ancestry rather than the earlier
copy-paste (#15661).
Conflicts resolved toward the reviewed lts-4.2 form for shared code
(explicit @EqualsAndHashCode(callSuper=true), typed StringUtils/removeStart,
imported test annotations). lts-4.3-only implementations kept as-is
(calculated-field state classes, native CF repository); tests removed on
lts-4.3 (CalculatedFieldLinkDataValidatorTest, DefaultDataUpdateServiceTest)
stay removed.