Target sanitize properties can disable the global sanitizer.

With this change, sanitize: { address: false } disables
SANITIZE_TARGET=address for one target.

Also rename SafeStack to Safestack, because the former can not be
used as a target property.

Bug: 27729263
Change-Id: I20f55c0e62b2fdd191ba66c0f661a039109bd78f