[infra] Update test.py help now that named configurations are implemented.

Change-Id: I6ca7fa2d14e95f3a09e01b5e721f3e5962abb525
Reviewed-on: https://dart-review.googlesource.com/c/92601
Reviewed-by: William Hesse <whesse@google.com>
diff --git a/tools/testing/dart/options.dart b/tools/testing/dart/options.dart
index 6208d66..0f0a789 100644
--- a/tools/testing/dart/options.dart
+++ b/tools/testing/dart/options.dart
@@ -147,8 +147,7 @@
     new _Option(
         'named_configuration',
         '''The named test configuration that supplies the values for all
-test options, specifying how tests should be run. Unimplemented
-currently.''',
+test options, specifying how tests should be run.''',
         abbr: 'n',
         hide: true),
     new _Option.bool('checked', 'Run tests in checked mode.'),