cleanup patch generation to preseve comments and remove @patch

test/dart_codegen/expect/_internal/symbol.dart

Index: test/dart_codegen/expect/_internal/symbol.dart
diff --git a/test/dart_codegen/expect/_internal/symbol.dart b/test/dart_codegen/expect/_internal/symbol.dart
index 19174f92e07771f06c8e3795252ba0eedc450579..1d5e453e842a943e65fa29cf3f378415d7cb5905 100644
--- a/test/dart_codegen/expect/_internal/symbol.dart
+++ b/test/dart_codegen/expect/_internal/symbol.dart
@@ -14,7 +14,7 @@ class Symbol implements core.Symbol {
       '^(?:$operatorRE\$|$publicIdentifierRE(?:=?\$|[.](?!\$)))+?\$');
   static final RegExp symbolPattern =
       new RegExp('^(?:$operatorRE\$|$identifierRE(?:=?\$|[.](?!\$)))+?\$');
-  @patch const Symbol(String name) : this._name = name;
+  const Symbol(String name) : this._name = name;
   const Symbol.unvalidated(this._name);
   Symbol.validated(String name) : this._name = validatePublicSymbol(name);
   bool operator ==(other) => other is Symbol && _name == other._name;