Don't implicitly run "pub get".

test/dart2js/does_not_support_invalid_option_test.dart

Index: test/dart2js/does_not_support_invalid_option_test.dart
diff --git a/test/dart2js/does_not_support_invalid_option_test.dart b/test/dart2js/does_not_support_invalid_option_test.dart
index ab4265565d0c738e0cfd278f70e54d1e09ad5c1a..b0777f31257d7163ba77cad4234a9d2f21d1b893 100644
--- a/test/dart2js/does_not_support_invalid_option_test.dart
+++ b/test/dart2js/does_not_support_invalid_option_test.dart
@@ -19,6 +19,8 @@ main() {
       })
     ]).create();
 
+    pubGet();
+
     // TODO(nweiz): This should provide more context about how the option got
     // passed to dart2js. See issue 16008.
     var pub = startPubServe();