fix token type of first token in converted token stream

pkg/front_end/lib/src/fasta/analyzer/token_utils.dart

Index: pkg/front_end/lib/src/fasta/analyzer/token_utils.dart
diff --git a/pkg/front_end/lib/src/fasta/analyzer/token_utils.dart b/pkg/front_end/lib/src/fasta/analyzer/token_utils.dart
index 08a6ce70b1d5d08a568712bd5ffc75c8337b8fac..debd20b5b9f14a5f528f90f105b48c6ddd783a20 100644
--- a/pkg/front_end/lib/src/fasta/analyzer/token_utils.dart
+++ b/pkg/front_end/lib/src/fasta/analyzer/token_utils.dart
@@ -92,7 +92,7 @@ class ToAnalyzerTokenStreamConverter {
   /// Converts a stream of Fasta tokens (starting with [token] and continuing to
   /// EOF) to a stream of analyzer tokens.
   analyzer.Token convertTokens(Token token) {
-    _analyzerTokenHead = new analyzer.Token(null, 0);
+    _analyzerTokenHead = new analyzer.Token(TokenType.EOF, -1);
     _analyzerTokenHead.previous = _analyzerTokenHead;
     _analyzerTokenTail = _analyzerTokenHead;
     _currentCommentHead = null;