[jdk24] RFR: 8349183: [BACKOUT] Optimization for StringBuilder append boolean & null

[Jaikiran Pai]

Can I please get a review of this backport of https://github.com/openjdk/jdk/pull/23420 into jdk24?

This proposes to bring in those same backouts into `jdk24` to prevent the issue noted in that PR description. jdk24 is in rampdown and this backport will require an approval. A approval request has been raised in https://bugs.openjdk.org/browse/JDK-8349183?focusedId=14746841&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-14746841.

This backport into jdk24 wasn't clean due to a trivial merge conflict in `StringLatin1.java` file. That merge conflict was manually resolved (just like it was done against mainline). The git commands used to create this backport against jdk24 branch are:


<checkout fresh jdk24 branch>
git cherry-pick --no-commit 618c5eb27b4c719afd577b690e6bcb21a45fcb0d
<resolve merge conflict in StringLatin1.java>
git commit -m 'Backport 618c5eb27b4c719afd577b690e6bcb21a45fcb0d'


tier1, tier2 and tier3 testing is currently in progress with this change.

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Commit messages:
 - Backport 618c5eb27b4c719afd577b690e6bcb21a45fcb0d

Changes: https://git.openjdk.org/jdk/pull/23425/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23425&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349183
  Stats: 169 lines in 6 files changed: 46 ins; 79 del; 44 mod
  Patch: https://git.openjdk.org/jdk/pull/23425.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23425/head:pull/23425

PR: https://git.openjdk.org/jdk/pull/23425