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

[Viktor Klang]

On Tue, 22 Jul 2025 07:10:14 GMT, Per Minborg <pminborg at openjdk.org> wrote:

>> 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

src/java.base/share/classes/java/util/ImmutableCollections.java line 1677:

> 1675: 
> 1676:                 private LazyMapIterator(StableMapEntrySet<K, V> outer) {
> 1677:                     this.underlyingHolder = outer.outer.underlyingHolder;

Might be worth a comment explaining the "outer.outer" part.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25878#discussion_r2267207161