[builtins] Move StringLocaleCompare to a builtin.

src/js/string.js

Index: src/js/string.js
diff --git a/src/js/string.js b/src/js/string.js
index 00fee68ac9fc6d02598c212d89f9af54d135b84a..da1643b06c9c2fb787acbb99d76261ef72431706 100644
--- a/src/js/string.js
+++ b/src/js/string.js
@@ -87,17 +87,6 @@ function StringLastIndexOf(pat, pos) {  // length == 1
 %FunctionSetLength(StringLastIndexOf, 1);
 
 
-// ECMA-262 section 15.5.4.9
-//
-// This function is implementation specific.  For now, we do not
-// do anything locale specific.
-function StringLocaleCompareJS(other) {
-  CHECK_OBJECT_COERCIBLE(this, "String.prototype.localeCompare");
-
-  return %StringLocaleCompare(TO_STRING(this), TO_STRING(other));
-}
-
-
 // ES6 21.1.3.11.
 function StringMatchJS(pattern) {
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.match");
@@ -714,7 +703,6 @@ utils.InstallFunctions(GlobalString.prototype, DONT_ENUM, [
   "includes", StringIncludes,
   "indexOf", StringIndexOf,
   "lastIndexOf", StringLastIndexOf,
-  "localeCompare", StringLocaleCompareJS,
   "match", StringMatchJS,
   "repeat", StringRepeat,
   "replace", StringReplace,