[dfsan] Tweaks for the ABI list

- Add a bunch of glibc functions to the ABI list
- Group similar functions in the ABI

Patch by Lorenzo Martignoni!

Differential Revision: http://llvm-reviews.chandlerc.com/D2185

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@195110 91177308-0d34-0410-b5e6-96231b3b80d8