RFR: Windows compiler does not support variable length arrays

[William Kemper]

Windows compiler does not support variable length arrays

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Commit messages:
 - Windows compiler does not support variable length arrays

Changes: https://git.openjdk.org/shenandoah/pull/151/files
 Webrev: https://webrevs.openjdk.org/?repo=shenandoah&pr=151&range=00
  Stats: 4 lines in 1 file changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/shenandoah/pull/151.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah pull/151/head:pull/151

PR: https://git.openjdk.org/shenandoah/pull/151