more fixes for fasta analyzer integration

pkg/analyzer/test/generated/utilities_test.dart

Index: pkg/analyzer/test/generated/utilities_test.dart
diff --git a/pkg/analyzer/test/generated/utilities_test.dart b/pkg/analyzer/test/generated/utilities_test.dart
index 51c4a56046b701c24f5087c15c998de76bba581b..640a9f341d1843cbd6857d17e29e46af069c8b16 100644
--- a/pkg/analyzer/test/generated/utilities_test.dart
+++ b/pkg/analyzer/test/generated/utilities_test.dart
@@ -61,7 +61,7 @@ class AstCloneComparator extends AstComparator {
       fail('Failed to copy token: ${first.lexeme} (${first.offset})');
       return false;
     }
-    if (first is TokenWithComment) {
+    if (first?.precedingComments != null) {
       CommentToken comment = first.precedingComments;
       if (comment.parent != first) {
         fail('Failed to link the comment "$comment" with the token "$first".');