[crac] RFR: 8348670: [CRaC] VirtualAllocCommitUncommitRecommit.java sometimes hangs

[Timofei Pushkin]

A `ThreadBlockInVM` guard had no effect because it had no name (it was destroyed immediately after creation) and that was causing a deadlock.

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Commit messages:
 - VirtualAllocCommitUncommitRecommit.java sometimes hangs

Changes: https://git.openjdk.org/crac/pull/191/files
  Webrev: https://webrevs.openjdk.org/?repo=crac&pr=191&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8348670
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/crac/pull/191.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/191/head:pull/191

PR: https://git.openjdk.org/crac/pull/191