Fix casing of parent classes and interfaces
Summary:
Class names are case insensitive in PHP.
Currently, class and interface names are saved case-insensitive in HPHP
trunk. This revision changes it so that the original case-sensitive
parent and interface classes are retained, and the various hash lookups
for classes use case-insensitive lookup for ClassScope.
Reviewers: mwilliams, andrewparoski, je, kma, oyamauchi
Test Plan: make fast_tests, slow_tests, flib tests. Compile www and
check that it works.
Revert: OK
Differential Revision: 319941