Improve MultiTextBase test stability and coverage
Improve MultiTextBase test stability and coverage

* Fix a test that will fail in mono4-sil because attribute
  order from a serializer is not guaranteed
* Delete commented out tests
* Re-introduce part of the functionality of a test that
  was commented out

gtryus/libpalaso,gmartin7/libpalaso,glasseyes/libpalaso,andrew-polk/libpalaso,andrew-polk/libpalaso,sillsdev/libpalaso,sillsdev/libpalaso,gmartin7/libpalaso,gtryus/libpalaso,andrew-polk/libpalaso,glasseyes/libpalaso,ermshiperete/libpalaso,sillsdev/libpalaso,glasseyes/libpalaso,gtryus/libpalaso,glasseyes/libpalaso,ermshiperete/libpalaso,gmartin7/libpalaso,andrew-polk/libpalaso,sillsdev/libpalaso,ermshiperete/libpalaso,ermshiperete/libpalaso,gmartin7/libpalaso,gtryus/libpalaso