[ASAN] Add the binder globals on Darwin to llvm.compiler.used to avoid LTO dead-stripping

[ASAN] Add the binder globals on Darwin to llvm.compiler.used to avoid LTO dead-stripping

The binder is in a specific section that "reverse" the edges in a
regular dead-stripping: the binder is live as long as a global it
references is live.

This is a big hammer that prevents LLVM from dead-stripping these,
while still allowing linker dead-stripping (with special knowledge
of the section).

Differential Revision: https://reviews.llvm.org/D24673

llvm-svn: 282988