[jdk17u-dev] RFR: 8283566: G1: Improve G1BarrierSet::enqueue performance

[Aleksey Shipilev]

Clean (after #905) backport to improve G1 performance.

Additional testing:
 - [x] Linux x86_64 fastdebug `tier1`
 - [x] Linux x86_64 fastdebug `tier2`

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Depends on: https://git.openjdk.org/jdk17u-dev/pull/905

Commit messages:
 - Backport 6ebf845ff7d758c99367488818427fcb7a5dbda9

Changes: https://git.openjdk.org/jdk17u-dev/pull/906/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=906&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8283566
  Stats: 46 lines in 4 files changed: 26 ins; 10 del; 10 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/906.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/906/head:pull/906

PR: https://git.openjdk.org/jdk17u-dev/pull/906