[PATCH] [asan] disable fast unwind on ARM

[Yury Gribov]

> Fast stack unwind should work on ARM for Clang-compiled code, no matter Android or not.
> It requires -marm -fno-omit-frame-pointer.

AFAIK supporting frame pointer violates standard ARM ABIs so this will force user to recompile complete stack (glibc and other system libs). That's perfectly fine for some users but I doubt about majority. Are we sure that fast_unwind_on_malloc should be default on platforms without default frame pointer?

http://reviews.llvm.org/D3814