RFR: 8351565: Implement JEP 502: Stable Values (Preview) [v47]

[Per Minborg]

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

Per Minborg has updated the pull request incrementally with one additional commit since the last revision:

  Only use partial functions

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/23972/files
  - new: https://git.openjdk.org/jdk/pull/23972/files/26b84e89..7e15e49e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23972&range=46
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23972&range=45-46

  Stats: 99 lines in 2 files changed: 57 ins; 27 del; 15 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