i965: Explicitly abort instead of exiting on batch failure

This avoids a deadlock condition when registered atexit handlers attempt to
acquire a mutex, but the program was going to exit with an error anyway

Reviewed-by: Marcin Ślusarz <marcin.slusarz@intel.com>
Reviewed-by: Rohan Garg <rohan.garg@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11813>

src/mesa/drivers/dri/i965/brw_batch.c

@@ -862,7 +862,7 @@ submit_batch(struct brw_context *brw, int in_fence_fd, int *out_fence_fd)
    if (ret != 0) {
       fprintf(stderr, "i965: Failed to submit batchbuffer: %s\n",
               strerror(-ret));
-      exit(1);
+      abort();
    }
 
    return ret;