RFR: JDK-8286666: JEP 429: Implementation of Scoped Values (Incubator) [v4]

[Andrew Haley]

> JEP 429 implementation.

Andrew Haley has updated the pull request incrementally with one additional commit since the last revision:

  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/442a04ef..c70945bf

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10952&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10952&range=02-03

  Stats: 10 lines in 5 files changed: 0 ins; 0 del; 10 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