Updated ReactNative findNodeHandle() to handle number case (#9238)

src/renderers/native/ReactNativeFiber.js

@@ -382,7 +382,10 @@ const ReactNative = {
   // See NativeMethodsMixin#setNativeProps for more info on why this is done.
   findNodeHandle(componentOrHandle: any): ?number {
     const instance: any = findNodeHandle(componentOrHandle);
-    return instance ? instance._nativeTag : null;
+    if (instance == null || typeof instance === 'number') {
+      return instance;
+    }
+    return instance._nativeTag;
   },
 
   render(element: Element<any>, containerTag: any, callback: ?Function) {

src/renderers/native/ReactNativeStack.js

@@ -37,7 +37,11 @@ var ReactNative = {
   // The injected findNodeHandle() strategy returns the instance wrapper though.
   // See NativeMethodsMixin#setNativeProps for more info on why this is done.
   findNodeHandle(componentOrHandle: any): ?number {
-    return findNodeHandle(componentOrHandle).getHostNode();
+    const nodeHandle = findNodeHandle(componentOrHandle);
+    if (nodeHandle == null || typeof nodeHandle === 'number') {
+      return nodeHandle;
+    }
+    return nodeHandle.getHostNode();
   },
 
   render: render,