RFR: 8341903: Implementation of Scoped Values (Fourth Preview) [v3]

[Andrew Haley]

> The fourth preview of scoped values.

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

 - Scoped values
 - Scoped values

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/21456/files
  - new: https://git.openjdk.org/jdk/pull/21456/files/0d178006..90a344a3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21456&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21456&range=01-02

  Stats: 4 lines in 2 files changed: 0 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/21456.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21456/head:pull/21456

PR: https://git.openjdk.org/jdk/pull/21456