Consolidate java grok patterns + test,tests,tests

Here is a proposal to update the JAVA grok patterns and a way to test them.
It contains or improves very good changes in other open PR #926 and #1384

here is the additional changes:
- Allow no_package classes
- Add comment in the pattern file about special cases
- Made Line Number in JAVASTACKTRACEPART  optional to cover special cases

+ yummy tests...

I'm sure one could further improve the test_utils DSL in this particular case of grok single pattern testing, @jordansissel I'm looking at you :eyes: