Create mock versions set and sort implementations.

dart/frog/leg/lib/js_helper.dart

Index: dart/frog/leg/lib/js_helper.dart
diff --git a/dart/frog/leg/lib/js_helper.dart b/dart/frog/leg/lib/js_helper.dart
index 5ba9b5df2b516fab0a780a18eaebb717d50f3b15..6c534e90f663c6203e24d558ce69cb792792849d 100644
--- a/dart/frog/leg/lib/js_helper.dart
+++ b/dart/frog/leg/lib/js_helper.dart
@@ -278,11 +278,9 @@ builtin$removeLast$0(var receiver) {
 
 builtin$filter$1(var receiver, var predicate) {
   checkNull(receiver);
-  if (isJsArray(receiver)) {
-    return JS('Object', @'$0.filter(function(v) { return $1(v) === true; })',
-              receiver, predicate);
-  }
-  return UNINTERCEPTED(receiver.filter(predicate));
+  if (!isJsArray(receiver)) return UNINTERCEPTED(receiver.filter(predicate));
+
+  return Collections.filter(receiver, [], predicate);
 }
 
 
@@ -809,6 +807,12 @@ builtin$some$1(receiver, f) {
   return Collections.some(receiver, f);
 }
 
+builtin$every$1(receiver, f) {
+  if (!isJsArray(receiver)) return UNINTERCEPTED(receiver.every(f));
+
+  return Collections.every(receiver, f);
+}
+
 builtin$sort$1(receiver, compare) {
   checkNull(receiver);
   if (!isJsArray(receiver)) return UNINTERCEPTED(receiver.sort(compare));