Fix stil-exists message

Change-Id: I8354cae8082dea4257ba607a65957688557b3d5e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2573397Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833508}

ui/file_manager/integration_tests/remote_call.js

@@ -265,7 +265,7 @@ class RemoteCall {
       const elements =
           await this.callRemoteTestUtil('deepQueryAllElements', appId, [query]);
       if (elements.length > 0) {
-        return pending(caller, 'Elements %j is still exists.', elements);
+        return pending(caller, 'Elements %j still exists.', elements);
       }
       return true;
     });