Run tests with ASan / UBSan enabled
ASan and UBSan can help diagnose memory / undefined behavior issues (see https://clang.llvm.org/docs/AddressSanitizer.html , https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html). We should run our tests with those enabled to catch potential issues as early as possible. Both ASan and UBSan should be included in the release of GCC we're currently using.