[asan] Preserve existing LD_PRELOAD setting on Android.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@217584 91177308-0d34-0410-b5e6-96231b3b80d8
[UBSan] Parse common flags from UBSAN_OPTIONS runtime variable even if
UBSan is combined with ASan.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@217616 91177308-0d34-0410-b5e6-96231b3b80d8
Revert r217616. Problems and complexity it introduces negate its benefit

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@217652 91177308-0d34-0410-b5e6-96231b3b80d8