[asan] Added assembly functions for x86/amd64 asan.

These are runtime support functions for inline assembly instrumentation.

Patch by Yuri Gorshenin.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@201402 91177308-0d34-0410-b5e6-96231b3b80d8