Delete ReactFeatureFlags.enableReactContextCleanupFix

Summary:
This diff deletes the flag ReactFeatureFlags.enableReactContextCleanupFix, the flag was disabled for many months, I just disable it.

changelog: [internal] internal

Reviewed By: genkikondo, makovkastar

Differential Revision: D33781628

fbshipit-source-id: 4b5e22adf9d30da5b85bbbde8bdc98d98f5e8891

ReactAndroid/src/main/java/com/facebook/react/bridge/ReactContext.java

@@ -23,7 +23,6 @@ import com.facebook.react.bridge.queue.MessageQueueThread;
 import com.facebook.react.bridge.queue.ReactQueueConfiguration;
 import com.facebook.react.common.LifecycleState;
 import com.facebook.react.common.ReactConstants;
-import com.facebook.react.config.ReactFeatureFlags;
 import java.lang.ref.WeakReference;
 import java.util.concurrent.CopyOnWriteArraySet;
 
@@ -320,11 +319,6 @@ public class ReactContext extends ContextWrapper {
     if (mCatalystInstance != null) {
       mCatalystInstance.destroy();
     }
-    if (ReactFeatureFlags.enableReactContextCleanupFix) {
-      mLifecycleEventListeners.clear();
-      mActivityEventListeners.clear();
-      mWindowFocusEventListeners.clear();
-    }
   }
 
   /** Should be called by the hosting Fragment in {@link Fragment#onActivityResult} */