[Analysis] Support aligned new/delete functions.

Summary:
Clang's __builtin_operator_new/delete was recently taught about the aligned allocation overloads (r328134). This patch makes LLVM aware of them as well.
This allows the compiler to perform certain optimizations including eliding new/delete calls.

Reviewers: rsmith, majnemer, dblaikie, vsk, bkramer

Reviewed By: bkramer

Subscribers: ckennelly, llvm-commits

Differential Revision: https://reviews.llvm.org/D44769

llvm-svn: 329215