Throw error on unrecognized test sections.

Our .test file parser used to not abort tests when there
is a malformed test/section. This patch changes that behavior
to report an error and treat the test as failed.

Quite a few tests were not well-formed, and were not executed
as a result. This patch fixes those tests.

Arguably, the test file parser should be more flexible in which places
to accept comments, but this patch does not address that problem.

Change-Id: If53358eb0cb958b68e51940b071e64c1d6c3ec6f
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/5279
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: jenkins