[DFSan] Add pthread and other functions to ABI list.

The non-pthread functions are all clear discard functions.

Some of the pthread ones could clear shadow, but aren't worth writing
custom wrappers for.  I can't think of any reasonable scenario where we
would pass tainted memory to these pthread functions.

Reviewed By: stephan.yichao.zhao

Differential Revision: https://reviews.llvm.org/D92877