-fsanitize=undefined is not the same thing as --enable-sanitizers. After commit47c823e("tests/docker: add sanitizers back to clang build", 2019-09-11) test-clang is almost duplicating the asan (test-debug) test, so partly revert commit47c823e5bwhile leaving ubsan enabled. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>