[crac] RFR: Put restored Java process on foreground instead of restorewait

[Radim Vansa]

Solves a scenario where we restore the process in background, `fg` it and then try to Ctrl+C interrupt it. 

The usefulness of this actually depends on https://github.com/CRaC/criu/pull/14

`criuengine` restorewait does not have tty on stdin/stdout/stderr, though one FD is open to tty; we have to find it.

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Commit messages:
 - Put restored Java process on foreground instead of restorewait

Changes: https://git.openjdk.org/crac/pull/133/files
 Webrev: https://webrevs.openjdk.org/?repo=crac&pr=133&range=00
  Stats: 31 lines in 1 file changed: 30 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/crac/pull/133.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/133/head:pull/133

PR: https://git.openjdk.org/crac/pull/133