Merge pull request #10962 from johanssj/Fix10949

Fix Reflect has method signature(s) per issue #10949 initial report

Author: mhegazy

src/lib/es2015.reflect.d.ts

@@ -6,8 +6,7 @@ declare namespace Reflect {
     function get(target: any, propertyKey: PropertyKey, receiver?: any): any;
     function getOwnPropertyDescriptor(target: any, propertyKey: PropertyKey): PropertyDescriptor;
     function getPrototypeOf(target: any): any;
-    function has(target: any, propertyKey: string): boolean;
-    function has(target: any, propertyKey: symbol): boolean;
+    function has(target: any, propertyKey: PropertyKey): boolean;
     function isExtensible(target: any): boolean;
     function ownKeys(target: any): Array<PropertyKey>;
     function preventExtensions(target: any): boolean;