[NETBEANS-5032] - update .gitignore to include a few test dirs..

[BradWalker]

When one does the following command:

$ANT_HOME/bin/ant test-platform

Numerous test related files get created that should be ignored..

[bwalker@localhost netbeans]$ git status
On branch master
Untracked files:
  (use "git add <file>..." to include in what will be committed)
        platform/o.n.bootstrap/test/unit/data/jars/agent/org/agent/HelloWorld.class
...
        platform/o.n.bootstrap/test/unit/data/jars/uses-api/usesapi/UsesPublicClass.class

nothing added to commit but untracked files present (use "git add" to track)

This change to .gitignore adds these directories to be ignored..