Resolve or add `@noinspectionreason` comment to all `@noinspection` suppressions

Added at https://github.com/checkstyle/contribution/issues/614, we need to do a few inspections at a time and send PRs to either fix violations, or explain why they must exist in the codebase.

Start by reading issue 614 and locating the existing @noinspection suppressions in the repository. Inspect a few at a time, then either fix the reported violations or document why each suppression must remain with an @noinspectionreason comment; submit the resulting changes as a PR.

Written by the indexing model from the issue text.