Split SetProperty(...attributes, strictmode) into AddProperty(...attributes) and SetProperty(...…

src/date.js

Index: src/date.js
diff --git a/src/date.js b/src/date.js
index c58903cc29c23f653f99e0baf4e61ab129ccee3f..b242e718f73f2c7d1ce467be7488d10bf4a89a68 100644
--- a/src/date.js
+++ b/src/date.js
@@ -763,7 +763,7 @@ function SetUpDate() {
   ));
 
   // Set up non-enumerable constructor property of the Date prototype object.
-  %SetProperty($Date.prototype, "constructor", $Date, DONT_ENUM);
+  %DefineProperty($Date.prototype, "constructor", $Date, DONT_ENUM);
 
   // Set up non-enumerable functions of the Date prototype object and
   // set their names.