YAML: Enable the YAMLParser tests.

YAML: Enable the YAMLParser tests.

This commit enables the tests located in test/YAMLParser directory.
Those tests were never actually enabled, as llvm-lit didn't pick up the
files with the 'data' extension. The commit renames those test files to files
with the 'test' extension so that llvm-lit would find them.

This commit also modifies yaml-bench so that it returns an error status
if an error occurred during parsing. It also adds the '-use-color'
command line option to yaml-bench (to make sure that file check matches
the error messages in the output stream).

This commit modifies some of the renamed tests so that they wouldn't
fail. It gets rid of XFAILs and uses the 'not' command instead for
some of the tests that have to fail during parsing. This commit
also adds some 'FIXME' comments to a couple of tests that are
supposed to fail but currently pass because of various bugs
in the implementation of the yaml parser.

Reviewers: Justin Bogner

Differential Revision: http://reviews.llvm.org/D9448

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236754 91177308-0d34-0410-b5e6-96231b3b80d8