[crac] RFR: Support passing extra options in CREngine

[Radim Vansa]

In addition to `-XX:CREngine=program` this adds support to `-XX:CREngine=program,key=value,anotherkey` that translates into invoking `program --key value --anotherkey`.

This generic parameters support is utilized in `criuengine` that accepts `--verbosity` and `--log-file` options and relays them to `criu`.

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Commit messages:
 - Support passing extra options in CREngine

Changes: https://git.openjdk.org/crac/pull/63/files
 Webrev: https://webrevs.openjdk.org/?repo=crac&pr=63&range=00
  Stats: 150 lines in 3 files changed: 124 ins; 5 del; 21 mod
  Patch: https://git.openjdk.org/crac/pull/63.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/63/head:pull/63

PR: https://git.openjdk.org/crac/pull/63