Change new List(n) to return fixed length list.

utils/lib/file_system_vm.dart

Index: utils/lib/file_system_vm.dart
diff --git a/utils/lib/file_system_vm.dart b/utils/lib/file_system_vm.dart
index cc0c05c582b4c51f673c2789dc556c776710e846..12fb712873de0e40654cfab2daf53d33f4431255 100644
--- a/utils/lib/file_system_vm.dart
+++ b/utils/lib/file_system_vm.dart
@@ -20,7 +20,7 @@ class VMFileSystem implements FileSystem {
   String readAll(String filename) {
     var file = (new File(filename)).openSync();
     var length = file.lengthSync();
-    var buffer = new List<int>.fixedLength(length);
+    var buffer = new List<int>(length);
     var bytes = file.readListSync(buffer, 0, length);
     file.closeSync();
     return new String.fromCharCodes(new Utf8Decoder(buffer).decodeRest());