align fasta.PrecedenceInfo.precedence with analyzer.TokenType.precedence

pkg/front_end/test/scanner_roundtrip_test.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:front_end/src/fasta/analyzer/token_utils.dart';
 import 'package:front_end/src/fasta/scanner/precedence.dart';
 import 'package:front_end/src/scanner/token.dart';
 import 'package:front_end/src/fasta/scanner/string_scanner.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
@@ skipping 245 matching lines @@
         new Set.from(operatorTokenTypes.map((tt) => tt.lexeme));
 
     for (PrecedenceInfo info in PrecedenceInfo.all) {
       assertIsOperator(info.value, operatorLexemes.contains(info.value));
     }
 
     for (TokenType tt in new List.from(allTokenTypes)) {
       assertIsOperator(tt.lexeme, operatorTokenTypes.contains(tt));
     }
   }
+
+  void test_precedence() {
+    for (TokenType tt in allTokenTypes) {
+      for (PrecedenceInfo info in PrecedenceInfo.all) {
+        if (info.value == tt.lexeme || info.value == tt.name.toLowerCase()) {
+          expect(tt.precedence, info.precedence, reason: tt.name);
+        }
+      }
+    }
+  }
 }