Removed code that is no longer needed

The removed functions were only in place for the Unity Extension and were no
longer being used anywhere in the code.

The functions have not been used for a while.  Until recently I did not have
the unit test coverage or the time to double check they were no longer in use.

Note: all code that has been removed has been explicitly marked as code that
could be changed at any time and it should not be used to access MsgArgs.

Change-Id: Ie3b86a0e57260a3ec5e1d89561dedf067698e96a