RFR: JDK-8286666: JEP 429: Implementation of Scoped Values (Incubator) [v12]

[Andrew Haley]

> JEP 429 implementation.

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

 - Reviewer feedback
 - Reviewer feedback

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Changes:
  - all: https://git.openjdk.org/jdk/pull/10952/files
  - new: https://git.openjdk.org/jdk/pull/10952/files/d9e5979f..22cdc1af

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10952&range=11
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10952&range=10-11

  Stats: 64 lines in 7 files changed: 30 ins; 19 del; 15 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