CFI: Move STL allocator blacklist to clang

Summary:
The regular expression to match STL allocators can't easily account for
C++ mangling compression and fails to match some valid instances of STL
allocators. Perform this logic in clang instead.

Motivated by crbug.com/751385.

Reviewers: pcc, kcc, llvm-commits

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D36291

llvm-svn: 310109