update fasta scanner to generate two types of comments

pkg/front_end/lib/src/scanner/token.dart

Index: pkg/front_end/lib/src/scanner/token.dart
diff --git a/pkg/front_end/lib/src/scanner/token.dart b/pkg/front_end/lib/src/scanner/token.dart
index b4138f75112f9b078fb87ad9eb5e62676e2af54b..34c308c255bb37435e990581ae21f13c0a45c1dd 100644
--- a/pkg/front_end/lib/src/scanner/token.dart
+++ b/pkg/front_end/lib/src/scanner/token.dart
@@ -899,13 +899,11 @@ abstract class TokenType {
 
   static const TokenType KEYWORD = fasta.KEYWORD_INFO;
 
-  static const TokenType MULTI_LINE_COMMENT =
-      const fasta.PrecedenceInfo(null, 'MULTI_LINE_COMMENT', 0, -1);
+  static const TokenType MULTI_LINE_COMMENT = fasta.MULTI_LINE_COMMENT_INFO;
 
   static const TokenType SCRIPT_TAG = fasta.SCRIPT_INFO;
 
-  static const TokenType SINGLE_LINE_COMMENT =
-      const fasta.PrecedenceInfo(null, 'SINGLE_LINE_COMMENT', 0, -1);
+  static const TokenType SINGLE_LINE_COMMENT = fasta.SINGLE_LINE_COMMENT_INFO;
 
   static const TokenType STRING = fasta.STRING_INFO;