cleanup fasta token classes

pkg/analyzer/lib/src/dart/ast/utilities.dart

Index: pkg/analyzer/lib/src/dart/ast/utilities.dart
diff --git a/pkg/analyzer/lib/src/dart/ast/utilities.dart b/pkg/analyzer/lib/src/dart/ast/utilities.dart
index a85b81b37766682f782ca647f1d9786b0846cfc3..eb1f70529063d516b53b1c2d63c76b8e3662c277 100644
--- a/pkg/analyzer/lib/src/dart/ast/utilities.dart
+++ b/pkg/analyzer/lib/src/dart/ast/utilities.dart
@@ -994,8 +994,7 @@ class AstCloner implements AstVisitor<AstNode> {
 
     token = nonComment(token);
     if (_lastCloned == null) {
-      _lastCloned = new Token(TokenType.EOF, -1);
-      _lastCloned.setNext(_lastCloned);
+      _lastCloned = new Token.eof(-1);
     }
     while (token != null) {
       Token clone = token.copy();