So it seems that the tests for yaml parses that use yaml-bench never actually ran because lit.cfg didn't include
the '.data' file extension that those tests have.
I've attached the patch that re-enables them by adding the '.data' extension to lit.cfg. But maybe it would
be better to rename all the tests in test/YAMLParser so they would use the '.test' file extension?
I've also fixed some tests that were failing for me there.