Fix usage of Boolean constructor

src/renderers/dom/fiber/ReactDOMFiber.js

@@ -288,7 +288,7 @@ var DOMRenderer = ReactFiberReconciler({
   },
 
   shouldDeprioritizeSubtree(type : string, props : Props) : boolean {
-    return Boolean(props.hidden);
+    return !!props.hidden;
   },
 
   createTextInstance(

src/renderers/noop/ReactNoop.js

@@ -102,7 +102,7 @@ var NoopRenderer = ReactFiberReconciler({
   resetTextContent(instance : Instance) : void {},
 
   shouldDeprioritizeSubtree(type : string, props : Props) : boolean {
-    return Boolean(props.hidden);
+    return !!props.hidden;
   },
 
   createTextInstance(