LUCENE-9787: Hunspell: speed up suggesting a bit by not creating a huge TreeSet

[donnerpeter]

Description

We only need 100 first elements, not need to compare the thousands of other roots among themselves

Solution

Use a PriorityQueue, trim it once it becomes larger then the limit

Tests

Nothing failing, but added suggestion checks in TestPerformance to track progress. For now suggesting is horribly slow :(

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended)
• I have developed this patch against the master branch.
• I have run ./gradlew check.
• I have added tests for my changes.
• I have added documentation for the Ref Guide (for Solr changes only).