Get rid of perf_hooks package in Flipper UI

Summary:
perf_hooks is no longer needed as these APIs are widely available in both browser and electron.

Still needed in unit tests, as they run from Node

Reviewed By: lblasa, aigoncharov

Differential Revision: D32648253

fbshipit-source-id: 5718ea99b57f96f6858311fd0815ad18c476c99e

desktop/flipper-ui-core/src/dispatcher/tracking.tsx

@@ -7,7 +7,6 @@
  * @format
  */
 
-import {performance} from 'perf_hooks';
 import EventEmitter from 'eventemitter3';
 
 import {State, Store} from '../reducers/index';