test: fix missed warning for non-experimental AbortController

Signed-off-by: James M Snell <jasnell@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/36240
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: Shelley Vohr <codebytere@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

test/parallel/test-eventtarget-memoryleakwarning.js

@@ -25,10 +25,6 @@ common.expectWarning({
      'Use events.setMaxListeners() to increase ' +
      'limit'],
   ],
-  ExperimentalWarning: [[
-    'AbortController is an experimental feature. This feature could change ' +
-    'at any time'
-  ]]
 });