Add tests for parseInteger for uppercase letters
Add tests for parseInteger for uppercase letters

To test the fix in the previous commit (fa40598).

ceylon/ceylon.language,jvasileff/ceylon.language,lucaswerkmeister/ceylon.language,unratito/ceylon.language,jvasileff/ceylon.language,ceylon/ceylon.language,unratito/ceylon.language,lucaswerkmeister/ceylon.language