RFR: ThreadDumper: wrong LOCKED

[Alex Menkov]

The changes fixes a bug when monitor is reported as `LOCKED` instead of `WAITING_TO_LOCK` when `pending_monitor` is not set (the condition was commented initially)

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Commit messages:
 - monitor_is_entered

Changes: https://git.openjdk.org/loom/pull/219/files
  Webrev: https://webrevs.openjdk.org/?repo=loom&pr=219&range=00
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/loom/pull/219.diff
  Fetch: git fetch https://git.openjdk.org/loom.git pull/219/head:pull/219

PR: https://git.openjdk.org/loom/pull/219