enable sanitizers on build job that tests x86_64 linux

Author: Jorge Aparicio

src/ci/docker/x86_64-gnu/Dockerfile

@@ -22,5 +22,5 @@ RUN curl -OL https://github.com/Yelp/dumb-init/releases/download/v1.2.0/dumb-ini
     rm dumb-init_*.deb
 ENTRYPOINT ["/usr/bin/dumb-init", "--"]
 
-ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu
+ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu --enable-sanitizers
 ENV SCRIPT python2.7 ../x.py test && python2.7 ../x.py dist