For inline asm:

- recognize string "{memory}" in the MI generation
- mark as mayload/maystore when there's a memory clobber constraint.

PR14859.

Patch by Krzysztof Parzyszek

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172228 91177308-0d34-0410-b5e6-96231b3b80d8