RFR: 8284614: on macOS "spindump" should be run from failure_handler as root

[Leonid Mesnik]

The fix is contributed by @plummercj actually.

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Commit messages:
 - fix

Changes: https://git.openjdk.org/jdk/pull/10730/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10730&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8284614
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/10730.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10730/head:pull/10730

PR: https://git.openjdk.org/jdk/pull/10730