[crac] RFR: Implement CRaC exit codes

[Roman Marchenko]

Implement CRaC exit codes in case it catches a signal.

This is a continuation of #46  inspired by [this comment](https://github.com/openjdk/crac/pull/46#discussion_r1122014722)

So, in case the child is terminated by a signal, CRaC should be terminated in similar way too, if possible. Otherwise it returns 128+n exit code as bash does.

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Commit messages:
 - Implented re-raising signals to terminate a parent process

Changes: https://git.openjdk.org/crac/pull/52/files
 Webrev: https://webrevs.openjdk.org/?repo=crac&pr=52&range=00
  Stats: 22 lines in 2 files changed: 22 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/crac/pull/52.diff
  Fetch: git fetch https://git.openjdk.org/crac pull/52/head:pull/52

PR: https://git.openjdk.org/crac/pull/52