RFR: 8307196: Dangling pointer warning for MetadataAllocationRequest [v2]

[Kim Barrett]

> Please review this change to work around a false positive -Wdangling-pointer
> warning from gcc13.1. The approach being taken is to suppress the warning,
> with a comment describing why it's a false positive.
> 
> As with JDK-8307147 I tried various code modifications to avoid the warning,
> but they were either obscure, or didn't seem reliably future-proof against
> further changes in gcc's analysis.
> 
> Testing:
> mach5 tier1-3 with gcc11.2 (current default in Oracle's CI)
> 
> Local (linux-x64) tier1 with gcc13.1, and verified the relevant warnings are
> not reported during the build. This required disabling compiler warnings as
> errors, as there are other new warnings from gcc13.1: JDK-8307210.

Kim Barrett 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 metaspace-dangling-pointer
 - disable metaspace warning

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13789/files
  - new: https://git.openjdk.org/jdk/pull/13789/files/5af06ed5..2f7f597a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13789&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13789&range=00-01

  Stats: 3337 lines in 65 files changed: 3099 ins; 125 del; 113 mod
  Patch: https://git.openjdk.org/jdk/pull/13789.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13789/head:pull/13789

PR: https://git.openjdk.org/jdk/pull/13789