String.prototype.{match,search} should do only one RegExp brand check

src/js/string.js

Index: src/js/string.js
diff --git a/src/js/string.js b/src/js/string.js
index 40fc099709fa5d6eb94baadf42bb20e000c91c78..498021381a5181e8420a4940ce5e0e4082301e65 100644
--- a/src/js/string.js
+++ b/src/js/string.js
@@ -20,6 +20,7 @@ var MakeRangeError;
 var MakeTypeError;
 var MaxSimple;
 var MinSimple;
+var RegExpInitialize;
 var matchSymbol = utils.ImportNow("match_symbol");
 var replaceSymbol = utils.ImportNow("replace_symbol");
 var searchSymbol = utils.ImportNow("search_symbol");
@@ -33,6 +34,7 @@ utils.Import(function(from) {
   MakeTypeError = from.MakeTypeError;
   MaxSimple = from.MaxSimple;
   MinSimple = from.MinSimple;
+  RegExpInitialize = from.RegExpInitialize;
 });
 
 //-------------------------------------------------------------------
@@ -159,8 +161,9 @@ function StringMatchJS(pattern) {
 
   var subject = TO_STRING(this);
 
-  // Non-regexp argument.
-  var regexp = new GlobalRegExp(pattern);
+  // Equivalent to RegExpCreate (ES#sec-regexpcreate)
+  var regexp = %NewObject(GlobalRegExp, GlobalRegExp);
+  RegExpInitialize(regexp, pattern);
   return regexp[matchSymbol](subject);
 }
 
@@ -355,7 +358,10 @@ function StringSearch(pattern) {
   }
 
   var subject = TO_STRING(this);
-  var regexp = new GlobalRegExp(pattern);
+
+  // Equivalent to RegExpCreate (ES#sec-regexpcreate)
+  var regexp = %NewObject(GlobalRegExp, GlobalRegExp);
+  RegExpInitialize(regexp, pattern);
   return %_Call(regexp[searchSymbol], regexp, subject);
 }