Back out "Reset RootView ID when root view is detached from view hierarchy"

Summary:
Original commit changeset: 5e607f34cf42

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D21757847

fbshipit-source-id: 96caf39f2ee99f64c96ebac9836ca178a7513cf1

ReactAndroid/src/main/java/com/facebook/react/ReactInstanceManager.java

@@ -840,9 +840,6 @@ public class ReactInstanceManager {
           detachViewFromInstance(reactRoot, currentContext.getCatalystInstance());
         }
       }
-
-      // Reset reactRoot content in case it's reused
-      clearReactRoot(reactRoot);
     }
   }