iOS: RCTSurface needs to re-register its root view on bridge reload

Summary: When reloading JS during development, surface needs to make sure the root view gets re-registered before attempting to remount it. This fixes redbox on JS reload.

Reviewed By: shergin

Differential Revision: D7170416

fbshipit-source-id: c84b999d2cdc35cb9e26feef2a1e1a7ce35cfa70

React/Base/Surface/RCTSurface.mm

@@ -209,6 +209,7 @@
   }
 
   if (isRerunNeeded) {
+    [self _registerRootView];
     [self _run];
   }
 }