Added individual suppression to spotbugs false positives

[StefanSpieker]

Added individual suppression to spotbugs false positives of type UNSAFE_HASH_EQUALS

Proposed changelog entries

• N/A

Proposed upgrade guidelines

N/A

Submitter checklist

• [ ] (If applicable) Jira issue is well described
• [ ] Changelog entries and upgrade guidelines are appropriate for the audience affected by the change (users or developer, depending on the change) and are in the imperative mood. Examples
  • Fill-in the Proposed changelog entries section only if there are breaking changes or other changes which may require extra steps from users during the upgrade
• [ ] Appropriate autotests or explanation to why this change has no tests
• [ ] New public classes, fields, and methods are annotated with @Restricted or have @since TODO Javadoc, as appropriate.
• [ ] New deprecations are annotated with @Deprecated(since = "TODO") or @Deprecated(forRemoval = true, since = "TODO") if applicable.
• [ ] New or substantially changed JavaScript is not defined inline and does not call eval to ease future introduction of Content-Security-Policy directives (see documentation on jenkins.io).
• [ ] For dependency updates: links to external changelogs and, if possible, full diffs

Desired reviewers

@mention

Maintainer checklist

Before the changes are marked as ready-for-merge:

• [ ] There are at least 2 approvals for the pull request and no outstanding requests for change
• [ ] Conversations in the pull request are over OR it is explicit that a reviewer does not block the change
• [ ] Changelog entries in the PR title and/or Proposed changelog entries are accurate, human-readable, and in the imperative mood
• [ ] Proper changelog labels are set so that the changelog can be generated automatically
• [ ] If the change needs additional upgrade steps from users, upgrade-guide-needed label is set and there is a Proposed upgrade guidelines section in the PR title. (example)
• [ ] If it would make sense to backport the change to LTS, a Jira issue must exist, be a Bug or Improvement, and be labeled as lts-candidate to be considered (see query).

[StefanSpieker]

It is a follow up of https://github.com/jenkinsci/jenkins/pull/6015 @basil added some classes to ignore, so that someone can work on triaging the remaining issues. This is a start, and I plan to continue working on these, if noone has objections, of course :)