Add a simple test for reproducibility

It probably needs environment changes and other differences to be more
effective, but if anything it adds a placeholder for improvement, and
shows some solidarity with the reproducible builds project that was
started in debian.

test.sh

@@ -28,3 +28,5 @@ fi
 if env | grep -q -e '^JENKINS_URL=' -e '^BUILD_TAG=jenkins'; then
 	./test/test-omv.sh
 fi
+
+./test/test-reproducible.sh