RFR: JDK-8286666: JEP 429: Implementation of Scoped Values (Incubator) [v21]

[Andrew Haley]

> JEP 429 implementation.

Andrew Haley has updated the pull request incrementally with three additional commits since the last revision:

 - Merge branch 'JDK-8286666' of https://github.com/theRealAph/jdk into JDK-8286666
 - Update src/java.base/share/classes/java/lang/VirtualThread.java
   
   Co-authored-by: Alan Bateman <Alan.Bateman at oracle.com>
 - Feedback from reviewers

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Changes:
  - all: https://git.openjdk.org/jdk/pull/10952/files
  - new: https://git.openjdk.org/jdk/pull/10952/files/b06ea927..dc577736

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10952&range=20
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10952&range=19-20

  Stats: 2 lines in 2 files changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/10952.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10952/head:pull/10952

PR: https://git.openjdk.org/jdk/pull/10952