[asan] Common flags in ASan.

Some flags that are common to ASan/MSan/TSan/LSan have been moved to
sanitizer_common.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@181193 91177308-0d34-0410-b5e6-96231b3b80d8
[msan] Common flags in MSan.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@181194 91177308-0d34-0410-b5e6-96231b3b80d8