[PATCH] Move GOTPass and StubsPass from Core to MachO

[kledzik at apple.com]

Those tests need the glue code also deleted from CoreLinkingContext.cpp. That glue code identifies call sites, etc and specific to the flavor.   I'll be adding new mach-o specific test cases for the passes as part of the refactoring I'm planning.

This came about because I was adding ARM support to mach-o and realized I would need to copy and paste lots of code from x86[_64] mach-o support.  I'd rather refactor it so there is less copying needed.

http://reviews.llvm.org/D4426