Disable sanitizers for libcore

libcore fails to build with the `-C link-dead-code` flag when building
fuzzers. Its not unreasonable to think we'll run into more problems when
applying sanitizers to libcore in the future, so lets disable them for
this sysroot.

Bug: 193200135
Test: fuzzer compiles successfully, runs.
Change-Id: I61fbabfc8e5f75d03fadd29fc131e112694a56cd
1 file changed