Give more time to the dart2js transformer tests.

sdk/lib/_internal/pub/test/transformer/dart2js/allows_import_in_dart_code_test.dart

Index: sdk/lib/_internal/pub/test/transformer/dart2js/allows_import_in_dart_code_test.dart
diff --git a/sdk/lib/_internal/pub/test/transformer/dart2js/allows_import_in_dart_code_test.dart b/sdk/lib/_internal/pub/test/transformer/dart2js/allows_import_in_dart_code_test.dart
index 441ef8bc09cf68838459fb7fab8d72a9af54d1e5..fc136fcede880c58b69e860a25b36e146508dbe6 100644
--- a/sdk/lib/_internal/pub/test/transformer/dart2js/allows_import_in_dart_code_test.dart
+++ b/sdk/lib/_internal/pub/test/transformer/dart2js/allows_import_in_dart_code_test.dart
@@ -13,6 +13,10 @@ import '../../serve/utils.dart';
 main() {
   initConfig();
   integration("handles imports in the Dart code", () {
+    // Dart2js can take a long time to compile dart code, so we increase the
+    // timeout to cope with that.
+    currentSchedule.timeout *= 3;
+
     d.dir("foo", [
       d.libPubspec("foo", "0.0.1"),
       d.dir("lib", [