[asan] Fix build on ARM.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@201652 91177308-0d34-0410-b5e6-96231b3b80d8
[asan] Disable asm instrumentation and tests on Mac.

Move asm tests to their own file.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@201653 91177308-0d34-0410-b5e6-96231b3b80d8