cleanup patch generation to preseve comments and remove @patch

test/dart_codegen/expect/collection/linked_hash_set.dart

Index: test/dart_codegen/expect/collection/linked_hash_set.dart
diff --git a/test/dart_codegen/expect/collection/linked_hash_set.dart b/test/dart_codegen/expect/collection/linked_hash_set.dart
index f6c334a5f1367c4d3d06650142beb0859d675446..2f866dcaf0a38c4ec27c887542968973e63484ce 100644
--- a/test/dart_codegen/expect/collection/linked_hash_set.dart
+++ b/test/dart_codegen/expect/collection/linked_hash_set.dart
@@ -1,7 +1,7 @@
 part of dart.collection;
 
 abstract class LinkedHashSet<E> implements HashSet<E> {
-  @patch factory LinkedHashSet({bool equals(E e1, E e2), int hashCode(E e),
+  factory LinkedHashSet({bool equals(E e1, E e2), int hashCode(E e),
       bool isValidKey(potentialKey)}) {
     if (isValidKey == null) {
       if (hashCode == null) {
@@ -28,7 +28,7 @@ abstract class LinkedHashSet<E> implements HashSet<E> {
     }
     return new _LinkedCustomHashSet<E>(equals, hashCode, isValidKey);
   }
-  @patch factory LinkedHashSet.identity() = _LinkedIdentityHashSet<E>;
+  factory LinkedHashSet.identity() = _LinkedIdentityHashSet<E>;
   factory LinkedHashSet.from(Iterable<E> elements) {
     LinkedHashSet<E> result = new LinkedHashSet<E>();
     for (final E element in elements) {