RFR: 8377150: G1: Full GC should not execute barrier code during reference processing

[Thomas Schatzl]

Hi all,

  please review this changes that removes execution of the (post-) barrier when enqueuing discovered references during full gc. It is simply not necessary as full gc throws away all remembered set information anyway later. Also allows adding checks that nobody else is executing G1BarrierSet code in the future.

Testing: gha, tier1-5

Thanks,
  Thomas

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

Commit messages:
 - 8377150

Changes: https://git.openjdk.org/jdk/pull/29564/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29564&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8377150
  Stats: 16 lines in 1 file changed: 15 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/29564.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29564/head:pull/29564

PR: https://git.openjdk.org/jdk/pull/29564