fail tests on threadlocal leaks [LUCENE-6335]

I know this requires us to do things like close our Analyzers in tests, but I think we should do it. just experimenting i found other leaks, e.g. in LineFileDocs.

```
[junit4] ERROR 0.00s J0 | TestForceMergeForever (suite) <<<
[junit4] > Throwable #1: java.lang.IllegalStateException: ThreadLocal leaks were found:
[junit4] > 1. thread=SUITE-TestForceMergeForever-seed#[AF7141C55A57350E]-worker value=WeakReference>
[junit4] > 2. thread=SUITE-TestForceMergeForever-seed#[AF7141C55A57350E]-worker value=LineFileDocs$DocState
```

---
Migrated from [LUCENE-6335](https://issues.apache.org/jira/browse/LUCENE-6335) by Robert Muir (@rmuir), updated Mar 05 2015
Attachments: [LUCENE-6335.patch](https://apache.github.io/lucene-jira-archive/attachments/LUCENE-6335/LUCENE-6335.patch) (versions: 3)

Start by reviewing the attached LUCENE-6335.patch and reproducing the thread-local leak reported by TestForceMergeForever. Inspect the Analyzer$TokenStreamComponents and LineFileDocs$DocState values named in the failure; done means the relevant tests no longer report thread-local leaks.

Written by the indexing model from the issue text.