[crac] RFR: Minor code cleanup and improvements

[Radim Vansa]

Extracted non-essential changes from other PR.

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Commit messages:
 - Minor code cleanup and improvements

Changes: https://git.openjdk.org/crac/pull/64/files
 Webrev: https://webrevs.openjdk.org/?repo=crac&pr=64&range=00
  Stats: 81 lines in 8 files changed: 47 ins; 16 del; 18 mod
  Patch: https://git.openjdk.org/crac/pull/64.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/64/head:pull/64

PR: https://git.openjdk.org/crac/pull/64