[jdk8u-dev] RFR: 8295714: GHA ::set-output is deprecated and will be removed

[zzambers]

Fixes warnings generated in GHA summary page by use of deprecated set-output command. According to warning messages command will be removed soon:

The `set-output` command is deprecated and will be disabled soon. Please upgrade to using Environment Files. For more information see: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/`

All tests passed (no warnings).

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Commit messages:
 - Backport 12ede6d6c6139db4ad1820f61236f9cfc81a874a

Changes: https://git.openjdk.org/jdk8u-dev/pull/172/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=172&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295714
  Stats: 9 lines in 1 file changed: 0 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/172.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev pull/172/head:pull/172

PR: https://git.openjdk.org/jdk8u-dev/pull/172