Revert "Fix case sensitivity for class methods."

This reverts commit fc525b7573b521c2115323bdaa9e6a1e972f9553.
Restore the ability to call ReflectionClass::getMethod with the wrong case.

This modifies the ReflectionClass class to obtain the proper name given the method identifier in the wrong case. This does require auxiliary space but the penalty is only paid if Reflection is used.

Fixes #1624 (for real!)