[gtest] Teach the sanitizer's custom gtest compilations to disable
a warning that 'gtest-all.cc' directly triggers in the newer 1.8.0
version.

This should fix a warning in folks' build and bring a couple of -Werror
bots back to life.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@291070 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed