RFR: 8293623: Simplify G1ConcurrentRefineThreadControl [v8]

[Lei Zaakjyu]

> 8293623: Simplify G1ConcurrentRefineThreadControl

Lei Zaakjyu has updated the pull request incrementally with one additional commit since the last revision:

  fix

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/17077/files
  - new: https://git.openjdk.org/jdk/pull/17077/files/4aa6f9f6..59aea1fb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17077&range=07
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17077&range=06-07

  Stats: 13 lines in 1 file changed: 11 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/17077.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17077/head:pull/17077

PR: https://git.openjdk.org/jdk/pull/17077