[jdk21u] RFR: 8316906: Clarify TLABWasteTargetPercent flag [v2]

[Ludvig Janiuk]

> Backporting a comment for a GC flag

Ludvig Janiuk has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'master' into JDK-8316906
 - Backort 77fac0f4c6692bcc06456d03a4329d9f8ddeeded

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

Changes:
  - all: https://git.openjdk.org/jdk21u/pull/225/files
  - new: https://git.openjdk.org/jdk21u/pull/225/files/8c3b4eed..c9ac91ce

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk21u&pr=225&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk21u&pr=225&range=00-01

  Stats: 1868 lines in 79 files changed: 1370 ins; 290 del; 208 mod
  Patch: https://git.openjdk.org/jdk21u/pull/225.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/225/head:pull/225

PR: https://git.openjdk.org/jdk21u/pull/225