Revert "js_runtime: streamline stringReplaceAllUnchecked"

sdk/lib/_internal/js_runtime/lib/string_helper.dart

Index: sdk/lib/_internal/js_runtime/lib/string_helper.dart
diff --git a/sdk/lib/_internal/js_runtime/lib/string_helper.dart b/sdk/lib/_internal/js_runtime/lib/string_helper.dart
index 904c5e913deed71e3d7749a82c452aa25c3b41ee..9ce91f8a179d7505935707a47ea45e8fef2c2f6d 100644
--- a/sdk/lib/_internal/js_runtime/lib/string_helper.dart
+++ b/sdk/lib/_internal/js_runtime/lib/string_helper.dart
@@ -130,6 +130,8 @@ stringReplaceFirstRE(receiver, regexp, replacement, startIndex) {
   return stringReplaceRangeUnchecked(receiver, start, end, replacement);
 }
 
+const String ESCAPE_REGEXP = r'[[\]{}()*+?.\\^$|]';
+
 stringReplaceAllUnchecked(receiver, pattern, replacement) {
   checkString(replacement);
   if (pattern is String) {
@@ -147,10 +149,8 @@ stringReplaceAllUnchecked(receiver, pattern, replacement) {
         return result.toString();
       }
     } else {
-      // Convert string [pattern] into a RegExp [replacer], escaping all
-      // metacharacters.
-      var quoted = JS('String',
-          r'#.replace(/[[\]{}()*+?.\\^$|]/g, "\\$&")', pattern);
+      var quoter = JS('', "new RegExp(#, 'g')", ESCAPE_REGEXP);
+      var quoted = JS('String', r'#.replace(#, "\\$&")', pattern, quoter);
       var replacer = JS('', "new RegExp(#, 'g')", quoted);
       return stringReplaceJS(receiver, replacer, replacement);
     }