[crac] RFR: Improve modules handling in initial FD bookkeeping

[Anton Kozlov]

Replace paths comparision with `os::same_file` which compares paths first, then compares st_{ino,dev}. This makes the check a bit more robust and fixes CRaC example-lambda [1]

Also, an annoying empty line is fixed in the warning, now that looks like:

anton at mercury:~/proj/crac$ ./jdk/bin/java -XX:CRaCCheckpointTo=./cr -version
[0.001s][warning][os] CRaC closing file descriptor 31: /dev/ptmx
openjdk version "17-internal" 2021-09-14
OpenJDK Runtime Environment (build 17-internal+0-adhoc..crac)
OpenJDK 64-Bit Server VM (build 17-internal+0-adhoc..crac, mixed mode)


[1] https://github.com/CRaC/example-lambda

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Commit messages:
 - Improve modules handling in initial FD bookkeeping

Changes: https://git.openjdk.org/crac/pull/59/files
 Webrev: https://webrevs.openjdk.org/?repo=crac&pr=59&range=00
  Stats: 16 lines in 1 file changed: 8 ins; 6 del; 2 mod
  Patch: https://git.openjdk.org/crac/pull/59.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/59/head:pull/59

PR: https://git.openjdk.org/crac/pull/59