(y)etsin fixes, test refactoring, and misc fixes

(y)etsin fixes, test refactoring, and misc fixes

* Fix etsin/етсин/этсин as noted in If933fc67845ac994d9ddfdf8349aff445ec9b13a
** only convert tsin to тсин and let the other rules sort out the e

* Refactor most tests to be word-specific, which uncovered a couple of
bugs in corner cases
** rol/üst prefix matches should match whole words (original [^ü] regex
assumed word could not be end of string

* Fixed incidental bugs I noticed while looking into the items above
** куркчи => kürkçi was in the wrong section
** cönk => джонк was in the right section, but reversed

* Added additional tests cases for all of the above.

Change-Id: Ia96be488a7b41c3ddba623b5c9262703b1c82687