flag to enable fasta scanner in analyzer

pkg/front_end/test/src/base/libraries_reader_test.dart

Index: pkg/front_end/test/src/base/libraries_reader_test.dart
diff --git a/pkg/front_end/test/src/base/libraries_reader_test.dart b/pkg/front_end/test/src/base/libraries_reader_test.dart
index 520e1ff66dcec511eaf663643253e4fc7e67a8c1..548fea0493764689cd53a07d46dde147ab634b12 100644
--- a/pkg/front_end/test/src/base/libraries_reader_test.dart
+++ b/pkg/front_end/test/src/base/libraries_reader_test.dart
@@ -227,7 +227,7 @@ const int VM_PLATFORM = 2;
 }
 
 class _Scanner extends Scanner {
-  _Scanner(String contents) : super(new CharSequenceReader(contents)) {
+  _Scanner(String contents) : super.create(new CharSequenceReader(contents)) {
     preserveComments = false;
   }