Add a new test file with some invalid comments and verify
they are filtered out of the mozGetMetadata() output.
The new file includes the following valid edge cases:
- empty tag name
- empty tag value
- punctuation in the tag name
and the following invalid cases:
- non-ascii tag name
- invalid characters in tag name
- non-utf-8 tag value
- no tag=value separator
Also updates the mochitest messages to be less confusing.
Ralph Giles