RFR: 8347994: Add additional diagnostics to macOS failure handler to assist with diagnosing MCast test failures

[serhiysachkov]

Add additional diagnostics to macOS failure handler to assist with diagnosing MCast test failures

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Commit messages:
 - 8347994: fixing trailing whitespace
 - 8347994: Add additional diagnostics to macOS failure handler to assist with diagnosing MCast test failures

Changes: https://git.openjdk.org/jdk/pull/23260/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23260&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8347994
  Stats: 7 lines in 1 file changed: 6 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/23260.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23260/head:pull/23260

PR: https://git.openjdk.org/jdk/pull/23260