Make RegExp's constructor non-const.

sdk/lib/_internal/compiler/implementation/lib/string_helper.dart

Index: sdk/lib/_internal/compiler/implementation/lib/string_helper.dart
diff --git a/sdk/lib/_internal/compiler/implementation/lib/string_helper.dart b/sdk/lib/_internal/compiler/implementation/lib/string_helper.dart
index 3a35778c677a431b508c26c8ed97d583c9c8b487..f70a975ac6666af26e3ff84154b97c9ec51140d8 100644
--- a/sdk/lib/_internal/compiler/implementation/lib/string_helper.dart
+++ b/sdk/lib/_internal/compiler/implementation/lib/string_helper.dart
@@ -75,6 +75,8 @@ stringReplaceJS(receiver, replacer, to) {
   return JS('String', r'#.replace(#, #)', receiver, replacer, to);
 }
 
+final RegExp quoteRegExp = new JSSyntaxRegExp(r'[-[\]{}()*+?.,\\^$|#\s]');
+
 stringReplaceAllUnchecked(receiver, from, to) {
   if (from is String) {
     if (from == "") {
@@ -91,8 +93,6 @@ stringReplaceAllUnchecked(receiver, from, to) {
         return result.toString();
       }
     } else {
-      RegExp quoteRegExp =
-          const JSSyntaxRegExp(r'[-[\]{}()*+?.,\\^$|#\s]');
       var quoter = regExpMakeNative(quoteRegExp, global: true);
       var quoted = JS('String', r'#.replace(#, "\\$&")', from, quoter);
       RegExp replaceRegExp = new JSSyntaxRegExp(quoted);