test: abstract parser test result

This patch introduce the new ParserTestResult class which is meant to
represent the result of a parser test.  I have refactored some methods
to take advantage of this new class.

It just hold the test description and the actual/expected parser output.
A short isSuccess() method is provided for convenience, we can later
improve the class to carry more methods.

Change-Id: Ifb86e09451875dc119633b52d3f7e4f47c67cc60
Merge "test: abstract parser test result"