LibJS: Implement basic functionality of Array.from()

The optional 2nd and 3rd arguments are not yet implemented.

This assumes that `this` is the Array constructor and doesn't yet
implement the more general behavior in the ES6 spec that allows
transferring this method to other constructors.

Libraries/LibJS/Runtime/ArrayConstructor.h

@@ -44,6 +44,7 @@ public:
 private:
     virtual bool has_constructor() const override { return true; }
 
+    JS_DECLARE_NATIVE_FUNCTION(from);
     JS_DECLARE_NATIVE_FUNCTION(is_array);
     JS_DECLARE_NATIVE_FUNCTION(of);
 };