Revert "light up sanitizers for ARM"

This commit broke the Windows build, where CMAKE_C_COMPILER can
compile and link with -march=armv7-a but the just-built-clang
cannot.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@209851 91177308-0d34-0410-b5e6-96231b3b80d8