[crac] RFR: 8351701: [CRaC] CRaCEngineOptions=help cannot be used with CRaCRestoreFrom

[Timofei Pushkin]

Fixes the issue and adds a regression test for it.

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Commit messages:
 - Fix CRE help with CRaCRestoreFrom

Changes: https://git.openjdk.org/crac/pull/211/files
  Webrev: https://webrevs.openjdk.org/?repo=crac&pr=211&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8351701
  Stats: 25 lines in 2 files changed: 18 ins; 4 del; 3 mod
  Patch: https://git.openjdk.org/crac/pull/211.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/211/head:pull/211

PR: https://git.openjdk.org/crac/pull/211