RFR: 8351565: Implement JEP 502: Stable Values (Preview) [v74]

[Per Minborg]

> Implement JEP 502.
> 
> The PR passes tier1-tier3 tests.

Per Minborg has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 365 commits:

 - Replace 'content' with 'contents' and doc updates
 - Merge branch 'master' into implement-jep502
 - Remove section on fun/coll sync
 - Reformat docs
 - Fix failing test (exception message)
 - Rework relayed to rethrown
 - Fix copyright related issues
 - Fix rawtype problem
 - Fix build problem
 - Resolve merge problem
 - ... and 355 more: https://git.openjdk.org/jdk/compare/27faf454...ac6accd8

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Changes: https://git.openjdk.org/jdk/pull/23972/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23972&range=73
  Stats: 4793 lines in 31 files changed: 4769 ins; 0 del; 24 mod
  Patch: https://git.openjdk.org/jdk/pull/23972.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23972/head:pull/23972

PR: https://git.openjdk.org/jdk/pull/23972