RFR: 8360884: Better scoped values [v5]

[Chen Liang]

On Thu, 3 Jul 2025 13:34:23 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> Scoped values cannot be used early in the JDK boot process because of some dependencies on System.getProperty(). This dependency should be removed in a way that allows scoped values to be created (but not necessarily bound) at any stage during boot.
>> 
>> Also, Scoped Value's constructor has a synchronized block, which limits the use of scoped values at runtime. Constructing a scoped value should be a thread-local operation.
>
> Andrew Haley has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Little things.

The latest updates to use stable static fields and to avoid double field read look good.

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Marked as reviewed by liach (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/26019#pullrequestreview-2983343085