RFR: 8344079: Minor fixes and cleanups to compiler lint-related code [v5]

[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.

Archie Cobbs has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains six commits:

 - Merge branch 'master' into JDK-8344079
 - Address review comment by being less Streamy.
 - Fold LintSuppression methods back into existing Lint class.
 - Merge branch 'master' into JDK-8344079
 - Fix typo in comment.
 - Minor lint-related cleanups.

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Changes: https://git.openjdk.org/jdk/pull/22056/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22056&range=04
  Stats: 159 lines in 3 files changed: 51 ins; 54 del; 54 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