[crac] RFR: Force closing a "redirected to the file" standard io descriptor

[Ilarion Nakonechnyy]

CRIU restore fail after Checkpoint stdout to file.
Redirecting a stdout to the pipeline doesn't break the restore. 

A proposed approach forces the close of stdout, stdin, and stderr file descriptors if they are redirected to the files, on checkpoint resources verification.

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Commit messages:
 - jchek corrections
 - corrections
 - corrections
 - Close stdin, stderr, stdout fd before checkpoint

Changes: https://git.openjdk.org/crac/pull/24/files
 Webrev: https://webrevs.openjdk.org/?repo=crac&pr=24&range=00
  Stats: 11 lines in 1 file changed: 11 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/crac/pull/24.diff
  Fetch: git fetch https://git.openjdk.org/crac pull/24/head:pull/24

PR: https://git.openjdk.org/crac/pull/24