[crac] RFR: 8348934: [CRaC] Drop CRTrace VM option

[Timofei Pushkin]

Obsoletes `CRTrace` VM option in favor of unified JVM logging.

Now it prints

[0.180s][info][crac] Checkpoint ...

rather than

CR: Checkpoint ...


Logging level for `crac` is programmatically set to `Info` (from the default `Warn`) and the level of a few other messages was reduced to `debug`.

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Commit messages:
 - Drop CRTrace VM option

Changes: https://git.openjdk.org/crac/pull/198/files
  Webrev: https://webrevs.openjdk.org/?repo=crac&pr=198&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8348934
  Stats: 29 lines in 5 files changed: 4 ins; 21 del; 4 mod
  Patch: https://git.openjdk.org/crac/pull/198.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/198/head:pull/198

PR: https://git.openjdk.org/crac/pull/198