RFR: 8359936: StableValues can release the underlying function after complete computation [v4]

[Per Minborg]

> This PR proposes to release the underlying function if a stable function or collection has invoked its underlying supplier exhaustively so that it can be collected.
> 
> This PR passes tier1, tier2, and tier3 testing on multiple platforms.

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

  Add a new method to StableValueImpl for improved speed

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25878/files
  - new: https://git.openjdk.org/jdk/pull/25878/files/d585f712..f9fd6ebb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25878&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25878&range=02-03

  Stats: 82 lines in 7 files changed: 26 ins; 29 del; 27 mod
  Patch: https://git.openjdk.org/jdk/pull/25878.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25878/head:pull/25878

PR: https://git.openjdk.org/jdk/pull/25878