[AggressiveInstCombine] Add aggressive inst combiner to the LLVM C API.

I just tried to copy what was done for regular InstCombine. Hopefully I didn't miss anything.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@330668 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed