[jdk17u-dev] RFR: 8301097: Update GHA XCode to 12.5.1

[Goetz Lindenmaier]

I think we should update the mac build environment.

I had to resolve. Trivial.

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Commit messages:
 - Backport b8e5abc1e8f5c7e2f0af675abb0e2ed481ffe128

Changes: https://git.openjdk.org/jdk17u-dev/pull/1566/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1566&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301097
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1566.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1566/head:pull/1566

PR: https://git.openjdk.org/jdk17u-dev/pull/1566