RFR: 8351565: Implement JEP 502: Stable Values (Preview)

[Per Minborg]

On Wed, 12 Mar 2025 14:38:28 GMT, Luca Kellermann <duke at openjdk.org> wrote:

>> This is something we experimented with a bit in the past. It isn't easy to do in the general case. There are pros (the function and its resources that can be collected) and cons (e.g., mutability, visibility, complexity, etc.) with this.
>
>> (Also `orElseSet` does not NPE if the incoming supplier is null but the value is bound)
> 
> You mean [this](https://github.com/openjdk/jdk/blob/a05717d8da8f804003cfb8d6d25b8a5b6cecd473/src/java.base/share/classes/jdk/internal/lang/stable/StableValueImpl.java#L117-L120) is missing `Objects.requireNonNull(supplier);`, right?

Fixed `Objects.requireNonNull()` now.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23972#discussion_r1993279982