[crac] RFR: 8347993: [CRaC] Assertion error in os::cleanup_memory()

[Timofei Pushkin]

Fixes an assertion error introduced with CRaC

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Commit messages:
 - Assertion error in os::cleanup_memory()

Changes: https://git.openjdk.org/crac/pull/185/files
  Webrev: https://webrevs.openjdk.org/?repo=crac&pr=185&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8347993
  Stats: 4 lines in 1 file changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/crac/pull/185.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/185/head:pull/185

PR: https://git.openjdk.org/crac/pull/185