Speculatively revert asan coverage changes 194702-194704.

Apple's bootstrapped LTO builds have been failing, and these changes (along
with llvm 194701) are the only things on the blamelist.  I will either reapply
these changes or help debug the problem, depending on whether this fixes the
buildbots.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@194779 91177308-0d34-0410-b5e6-96231b3b80d8