Remove ToObject on elements from Array.prototype.toLocaleString()

In ES5, ToObject was called on elements before invoking the
.toLocaleString() method on them. ES2015 specifies that ToObject is
not called. A test262 test verifies this change. This patch
implements the new ES2015 behavior. It is verified by the test262 test
built-ins/Array/prototype/toLocaleString/primitive_this_value_getter

R=adamk

Review URL: https://codereview.chromium.org/1390893003

Cr-Commit-Position: refs/heads/master@{#31160}

src/array.js

@@ -217,11 +217,7 @@ function ConvertToLocaleString(e) {
   if (IS_NULL_OR_UNDEFINED(e)) {
     return '';
   } else {
-    // According to ES5, section 15.4.4.3, the toLocaleString conversion
-    // must throw a TypeError if ToObject(e).toLocaleString isn't
-    // callable.
-    var e_obj = TO_OBJECT(e);
-    return TO_STRING(e_obj.toLocaleString());
+    return TO_STRING(e.toLocaleString());
   }
 }