Make List.from and Iterable.toList default to not growable.

pkg/scheduled_test/lib/src/schedule.dart

Index: pkg/scheduled_test/lib/src/schedule.dart
diff --git a/pkg/scheduled_test/lib/src/schedule.dart b/pkg/scheduled_test/lib/src/schedule.dart
index b2a4c8977919e6f464003347b140a31a1e2b40de..17ab86adfdba4f4363a4e41c5ea8f69dbfbeed3d 100644
--- a/pkg/scheduled_test/lib/src/schedule.dart
+++ b/pkg/scheduled_test/lib/src/schedule.dart
@@ -471,7 +471,8 @@ class TaskQueue {
       var lines = task.toString().split("\n");
       var firstLine = task == highlight ?
           "> ${lines.first}" : "* ${lines.first}";
-      lines = [firstLine]..addAll(lines.skip(1).map((line) => "| $line"));
+      lines = new List.from(lines.skip(1).map((line) => "| $line"));
+      lines.insertRange(0, 1, firstLine);
       return lines.join("\n");
     }).join("\n");
   }