Test shift + up/down keys work fine even when autofill popup window is shown.

1. Type the text 'hogehoge' in the following text input area. And press ENTER to submit.
2. Return to this page.
3. Type the text 'hoge' and make sure autofill popup window is shown.
4. Move back the cursor two steps at the center between 'o' and 'g'.
5. Press 'shift + up' key and make sure the 'ho' is selected even when autofill popup window is shown.
6. Press 'shift + down' key and make sure the 'ge' is selected even when autofill popup window is shown.
7. Use control/alt/command(only on Mac) modifier and check if they work fine too.