[CSS Grid Layout] Adapting align-self, align-items and justify-self to the last CSS 3 spec.

LayoutTests/fast/alignment/resources/alignment-parsing-utils.js

 function checkValues(element, property, propertyID, value, computedValue)
 {
     window.element = element;
     var elementID = element.id || "element";
     shouldBeEqualToString("element.style." + property, value);
     shouldBeEqualToString("window.getComputedStyle(" + elementID + ", '').getPropertyValue('" + propertyID + "')", computedValue);
 }
 
 function checkBadValues(element, property, propertyID, value)
 {
-    element.style.justifyItems = value;
+    element.style[property] = value;
     checkValues(element, property, propertyID, "", "start");
 }
 
 function checkInitialValues(element, property, propertyID, display, value)
 {
     var initial = "start";
     if (display == "grid" || display == "flex") {
       element.style.display = display;
       initial = "stretch";
     }
 
-    element.style.justifyItems = value;
+    element.style[property] = value;
     checkValues(element, property, propertyID, value, value);
-    element.style.justifyItems = "initial";
+    element.style[property] = "initial";
     checkValues(element, property, propertyID, "initial", initial);
 }
 
 function checkInheritValues(element, property, propertyID, value)
 {
     parentElement = document.createElement("div");
     document.body.appendChild(parentElement);
-    parentElement.style.justifyItems = value;
+    parentElement.style[property] = value;
     checkValues(parentElement, property, propertyID, value, value);
 
     element = document.createElement("div");
     parentElement.appendChild(element);
-    element.style.justifyItems = "inherit";
+    element.style[property] = "inherit";
     checkValues(element, property, propertyID, "inherit", value);
 }
 
 function checkLegacyValues(element, property, propertyID, value)
 {
     document.body.appendChild(parentElement);
-    parentElement.style.justifyItems = value;
+    parentElement.style[property] = value;
     checkValues(parentElement, property, propertyID, value, value);
 
     element = document.createElement("div");
     parentElement.appendChild(element);
     checkValues(element, property, propertyID, "", value);
 }