cleanup patch generation to preseve comments and remove @patch

test/dart_codegen/expect/core/string.dart

 part of dart.core;
 
 abstract class String implements Comparable<String>, Pattern {
-  @patch factory String.fromCharCodes(Iterable<int> charCodes,
+  factory String.fromCharCodes(Iterable<int> charCodes,
       [int start = 0, int end]) {
     if (charCodes is! JSArray) {
       return ((__x36) => DDC$RT.cast(__x36, dynamic, String, "CastGeneral",
-          """line 99, column 15 of dart:core/string.dart: """, __x36 is String,
+          """line 118, column 15 of dart:core/string.dart: """, __x36 is String,
           true))(_stringFromIterable(charCodes, start, end));
     }
     List list = DDC$RT.cast(charCodes, DDC$RT.type((Iterable<int> _) {}),
         DDC$RT.type((List<dynamic> _) {}), "CastGeneral",
-        """line 102, column 18 of dart:core/string.dart: """,
+        """line 121, column 18 of dart:core/string.dart: """,
         charCodes is List<dynamic>, true);
     int len = list.length;
     if (start < 0 || start > len) {
       throw new RangeError.range(start, 0, len);
     }
     if (end == null) {
       end = len;
     } else if (end < start || end > len) {
       throw new RangeError.range(end, start, len);
     }
     if (start > 0 || end < len) {
       list = list.sublist(start, end);
     }
     return ((__x37) => DDC$RT.cast(__x37, dynamic, String, "CastGeneral",
-        """line 116, column 13 of dart:core/string.dart: """, __x37 is String,
+        """line 135, column 13 of dart:core/string.dart: """, __x37 is String,
         true))(Primitives.stringFromCharCodes(list));
   }
-  @patch factory String.fromCharCode(int charCode) {
+  factory String.fromCharCode(int charCode) {
     return ((__x38) => DDC$RT.cast(__x38, dynamic, String, "CastGeneral",
-        """line 121, column 13 of dart:core/string.dart: """, __x38 is String,
+        """line 149, column 13 of dart:core/string.dart: """, __x38 is String,
         true))(Primitives.stringFromCharCode(charCode));
   }
-  @patch factory String.fromEnvironment(String name, {String defaultValue}) {
+  factory String.fromEnvironment(String name, {String defaultValue}) {
     throw new UnsupportedError(
         'String.fromEnvironment can only be used as a const constructor');
   }
   String operator [](int index);
   int codeUnitAt(int index);
   int get length;
   int get hashCode;
   bool operator ==(Object other);
   bool endsWith(String other);
   bool startsWith(Pattern pattern, [int index = 0]);
@@ skipping 63 matching lines @@
   }
   void _checkSplitSurrogate(int index) {
     if (index > 0 &&
         index < string.length &&
         _isLeadSurrogate(string.codeUnitAt(index - 1)) &&
         _isTrailSurrogate(string.codeUnitAt(index))) {
       throw new ArgumentError('Index inside surrogate pair: $index');
     }
   }
   int get rawIndex => ((__x39) => DDC$RT.cast(__x39, dynamic, int,
-      "CastGeneral", """line 645, column 24 of dart:core/string.dart: """,
+      "CastGeneral", """line 690, column 24 of dart:core/string.dart: """,
       __x39 is int, true))((_position != _nextPosition) ? _position : null);
   void set rawIndex(int rawIndex) {
     RangeError.checkValidIndex(rawIndex, string, "rawIndex");
     reset(rawIndex);
     moveNext();
   }
   void reset([int rawIndex = 0]) {
     RangeError.checkValueInInterval(rawIndex, 0, string.length, "rawIndex");
     _checkSplitSurrogate(rawIndex);
     _position = _nextPosition = rawIndex;
     _currentCodePoint = null;
   }
   int get current => DDC$RT.cast(_currentCodePoint, num, int, "CastGeneral",
-      """line 682, column 23 of dart:core/string.dart: """,
+      """line 727, column 23 of dart:core/string.dart: """,
       _currentCodePoint is int, true);
   int get currentSize => _nextPosition - _position;
   String get currentAsString {
     if (_position == _nextPosition) return null;
     if (_position + 1 == _nextPosition) return string[_position];
     return string.substring(_position, _nextPosition);
   }
   bool moveNext() {
     _position = _nextPosition;
     if (_position == string.length) {
@@ skipping 28 matching lines @@
         _position = position - 1;
         _currentCodePoint = _combineSurrogatePair(prevCodeUnit, codeUnit);
         return true;
       }
     }
     _position = position;
     _currentCodePoint = codeUnit;
     return true;
   }
 }