Backed out changeset dd82a78059af (bug 1454123) for devtools failures at devtools/client/webconsole/test/mochitest/browser_webconsole_split.js a=backout

devtools/client/webconsole/test/mochitest/browser_webconsole_split.js

@@ -29,14 +29,6 @@ add_task(async function() {
   checkHostType(Toolbox.HostType.SIDE);
   checkToolboxUI();
   await toolbox.switchHost(Toolbox.HostType.WINDOW);
-
-  // checkHostType, below,  will open the meatball menu to read the "Split
-  // console" menu item label. However, if we've just opened a new window then
-  // on some platforms when we switch focus to the new window we might end up
-  // triggering the auto-close behavior on the menu popup. To avoid that, wait
-  // a moment before querying the menu.
-  await new Promise(resolve => requestIdleCallback(resolve));
-
   checkHostType(Toolbox.HostType.WINDOW);
   checkToolboxUI();
   await toolbox.switchHost(Toolbox.HostType.BOTTOM);