Test for https://bugs.webkit.org/show_bug.cgi?id=31539

## Manual test for https://bugs.webkit.org/show_bug.cgi?id=31539.

To run this test:

- Change the text in the <textarea> below.
- Submit the form. The form should navigate back immediately.
- Note that the value in the text area matches what you entered before submitting the form, this is correct.
- Now click the reset button for the form.
- The text in the <textarea> should now match '123', the default text for the <textarea>.