Fix LT-22121: Analyze guesser should not guess ras for rAs (#327)

* Fix LT-22121: Analysis guesser should not guess ras for rAs

* Add test case for mixed case words

* Fix LT-22121: Analysis guesser should not guess ras for rAs

* Fix bugs and deal with all upper case

* Refactor HasContextCounts to have no side effects

Author: jtmaxwell3