cleanup patch generation to preseve comments and remove @patch

test/dart_codegen/expect/core/list.dart

Index: test/dart_codegen/expect/core/list.dart
diff --git a/test/dart_codegen/expect/core/list.dart b/test/dart_codegen/expect/core/list.dart
index d65eaa126557ee5856140e6898d2bffcfa45bb02..e93f86604ca926417917e1507f73b915bcb17971 100644
--- a/test/dart_codegen/expect/core/list.dart
+++ b/test/dart_codegen/expect/core/list.dart
@@ -1,21 +1,21 @@
 part of dart.core;
 
 abstract class List<E> implements Iterable<E>, EfficientLength {
-  @patch factory List([int length = const _ListConstructorSentinel()]) {
+  factory List([int length = const _ListConstructorSentinel()]) {
     if (length == const _ListConstructorSentinel()) {
       return ((__x26) => DDC$RT.cast(__x26, dynamic,
           DDC$RT.type((List<E> _) {}), "CastExact",
-          """line 58, column 14 of dart:core/list.dart: """, __x26 is List<E>,
+          """line 79, column 14 of dart:core/list.dart: """, __x26 is List<E>,
           false))(new JSArray<E>.emptyGrowable());
     }
     return ((__x27) => DDC$RT.cast(__x27, dynamic, DDC$RT.type((List<E> _) {}),
-        "CastExact", """line 60, column 12 of dart:core/list.dart: """,
+        "CastExact", """line 81, column 12 of dart:core/list.dart: """,
         __x27 is List<E>, false))(new JSArray<E>.fixed(length));
   }
-  @patch factory List.filled(int length, E fill) {
+  factory List.filled(int length, E fill) {
     List result = ((__x28) => DDC$RT.cast(__x28, dynamic,
         DDC$RT.type((List<dynamic> _) {}), "CastExact",
-        """line 65, column 19 of dart:core/list.dart: """,
+        """line 93, column 19 of dart:core/list.dart: """,
         __x28 is List<dynamic>, true))(new JSArray<E>.fixed(length));
     if (length != 0 && fill != null) {
       for (int i = 0; i < result.length; i++) {
@@ -24,10 +24,10 @@ abstract class List<E> implements Iterable<E>, EfficientLength {
     }
     return DDC$RT.cast(result, DDC$RT.type((List<dynamic> _) {}),
         DDC$RT.type((List<E> _) {}), "CastDynamic",
-        """line 71, column 12 of dart:core/list.dart: """, result is List<E>,
+        """line 99, column 12 of dart:core/list.dart: """, result is List<E>,
         false);
   }
-  @patch factory List.from(Iterable elements, {bool growable: true}) {
+  factory List.from(Iterable elements, {bool growable: true}) {
     List<E> list = new List<E>();
     for (E e in elements) {
       list.add(e);
@@ -35,7 +35,7 @@ abstract class List<E> implements Iterable<E>, EfficientLength {
     if (growable) return list;
     return ((__x29) => DDC$RT.cast(__x29, DDC$RT.type((List<dynamic> _) {}),
         DDC$RT.type((List<E> _) {}), "CastDynamic",
-        """line 81, column 12 of dart:core/list.dart: """, __x29 is List<E>,
+        """line 116, column 12 of dart:core/list.dart: """, __x29 is List<E>,
         false))(makeListFixedLength(list));
   }
   factory List.generate(int length, E generator(int index),