RFR: 8344079: Minor fixes and cleanups to compiler lint-related code

[Archie Cobbs]

Please review these changes with some minor lint-related fixes and cleanups.

See [JDK-8344079](https://bugs.openjdk.org/browse/JDK-8344079) for a more detailed description.

-------------

Commit messages:
 - Fix typo in comment.
 - Minor lint-related cleanups.

Changes: https://git.openjdk.org/jdk/pull/22056/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22056&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344079
  Stats: 273 lines in 8 files changed: 137 ins; 85 del; 51 mod
  Patch: https://git.openjdk.org/jdk/pull/22056.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22056/head:pull/22056

PR: https://git.openjdk.org/jdk/pull/22056