Add Scudo support for Make

Scudo is a hardened usermode allocator that is part of LLVM's compiler-rt
project (home of the Sanitizers). clang allows for -fsanitize=scudo as a
possible command line option to link the shared Scudo library to a binary.

This patch add Scudo as a potential sanitize option. Scudo is not compatible
with ASan and TSan and will be disabled if either is enabled.

Test: aosp compiled with m -j
Test: local experiment with LOCAL_SANITIZE := scudo to ensure that a test
target (mediaserver) could be linked with scudo.

Change-Id: I462843b9d5512fba2c4a3ac1a0c356ca90bce4e5