webrev for type-annotations, repeating type-annotations test

[Steve Sides]

This test supercedes the test in the previous review request (which was 
via mail).
http://cr.openjdk.java.net/~ssides/8005085/

In writing a test for repeating type annotations I found it could cover 
several scenarios in one test, so this coverage
mixed target types on type usages and type parameters as well as 
repeating type annotations in those usages.

Due to http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8005681 a few 
scenarios are commented out.
In addition to any other changes or suggestions, we may want for that to 
be fixed so the whole test can be considered.

This also include the previous refactoring of the classfile tests into a 
helper, ClassfileTestHelper.java.
This makes the tests much simpler looking and easier to add new tests.

I'd appreciate any comments or suggestions.

-steve