cleanup patch generation to preseve comments and remove @patch

test/generated_sdk/lib/collection/linked_hash_map.dart

Index: test/generated_sdk/lib/collection/linked_hash_map.dart
diff --git a/test/generated_sdk/lib/collection/linked_hash_map.dart b/test/generated_sdk/lib/collection/linked_hash_map.dart
index b381af9b5782996b9297f0fd38043f17eef0fc95..ecf78432e1ca951f562ef5744cbe125d17bf5831 100644
--- a/test/generated_sdk/lib/collection/linked_hash_map.dart
+++ b/test/generated_sdk/lib/collection/linked_hash_map.dart
@@ -24,7 +24,35 @@ part of dart.collection;
  * The map allows `null` as a key.
  */
 abstract class LinkedHashMap<K, V> implements HashMap<K, V> {
-  @patch
+  /**
+   * Creates an insertion-ordered hash-table based [Map].
+   *
+   * If [equals] is provided, it is used to compare the keys in the table with
+   * new keys. If [equals] is omitted, the key's own [Object.operator==] is used
+   * instead.
+   *
+   * Similar, if [hashCode] is provided, it is used to produce a hash value
+   * for keys in order to place them in the hash table. If it is omitted, the
+   * key's own [Object.hashCode] is used.
+   *
+   * If using methods like [operator[]], [remove] and [containsKey] together
+   * with a custom equality and hashcode, an extra `isValidKey` function
+   * can be supplied. This function is called before calling [equals] or
+   * [hashCode] with an argument that may not be a [K] instance, and if the
+   * call returns false, the key is assumed to not be in the set.
+   * The [isValidKey] function defaults to just testing if the object is a
+   * [K] instance.
+   *
+   * The used `equals` and `hashCode` method should always be consistent,
+   * so that if `equals(a, b)` then `hashCode(a) == hashCode(b)`. The hash
+   * of an object, or what it compares equal to, should not change while the
+   * object is in the table. If it does change, the result is unpredictable.
+   *
+   * If you supply one of [equals] and [hashCode],
+   * you should generally also to supply the other.
+   * An example would be using [identical] and [identityHashCode],
+   * which is equivalent to using the shorthand [LinkedHashMap.identity]).
+   */
   factory LinkedHashMap({ bool equals(K key1, K key2),
                           int hashCode(K key),
                           bool isValidKey(potentialKey) }) {
@@ -54,7 +82,13 @@ abstract class LinkedHashMap<K, V> implements HashMap<K, V> {
     return new _LinkedCustomHashMap<K, V>(equals, hashCode, isValidKey);
   }
 
-  @patch
+  /**
+   * Creates an insertion-ordered identity-based map.
+   *
+   * Effectively a shorthand for:
+   *
+   *     new LinkedHashMap(equals: identical, hashCode: identityHashCodeOf)
+   */
   factory LinkedHashMap.identity() = _LinkedIdentityHashMap<K, V>;
 
   /**