[crac] RFR: 8348929: [CRaC] Use /tmp for restore parameters storage

[Timofei Pushkin]

`CracSHM` now uses a file in `os::get_temp_directory()` instead of `shm_open`

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Commit messages:
 - Use /tmp for restore parameters storage

Changes: https://git.openjdk.org/crac/pull/197/files
  Webrev: https://webrevs.openjdk.org/?repo=crac&pr=197&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8348929
  Stats: 42 lines in 4 files changed: 17 ins; 19 del; 6 mod
  Patch: https://git.openjdk.org/crac/pull/197.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/197/head:pull/197

PR: https://git.openjdk.org/crac/pull/197