read_write_all: fix leak in tests.

ccan/read_write_all/test/run-read_all.c

@@ -71,5 +71,6 @@ int main(int argc, char *argv[])
 	ok(WIFEXITED(status) && WEXITSTATUS(status) == 0,
 	   "WIFEXITED(status) = %u, WEXITSTATUS(status) = %u",
 	   WIFEXITED(status), WEXITSTATUS(status));
+	free(buffer);
 	return exit_status();
 }

ccan/read_write_all/test/run-write_all.c

@@ -62,6 +62,7 @@ int main(int argc, char *argv[])
 	write_return = BUFSZ;
 	ok1(write_all(100, buffer, BUFSZ));
 	ok1(errno == 0);
+	free(buffer);
 
 	return exit_status();
 }