[compiler-rt] [Fuzzer] Enable custom libc++ for Android (PR #70407)

[Ryan Prichard via llvm-commits]

rprichard wrote:

> I don't see where the sanitizer buildbot is defining COMPILER_RT_USE_LIBCXX, but it looks like my attempt to reproduce the issue locally just finished, so I'll take a look.

Oh, it defaults to ON.

Anyway, I'm experimenting with an llvm-zorg fix that removes the redundant `-stdlib=libc++ -I/$ANDROID_TOOLCHAIN/sysroot/usr/include/c++/v1` flags in `$ANDROID_CXX_FLAGS`.



https://github.com/llvm/llvm-project/pull/70407