Fix a pair of compilation failure bugs in test files due to r5576.

Fix a pair of compilation failure bugs in test files due to r5576.

1. parser.h depends on ast.h, but only gets it included implicitly
   everywhere parser.h is included (except for tests).  Include ast.h in
   parser.h.

2. Regular expression tests test the free functions that have just been
   moved into class Parser.

TBR=fschneider@chromium.org

Committed: http://code.google.com/p/v8/source/detail?r=5577