Fix bad Oneof3.pdf test case.

The key/mouse events sent to the test PDF did not unfocus the second
form field. As a result, its value has not been saved. Change the other
Oneof test cases to consistently focus on the same result field.

BUG=pdfium:781

Change-Id: I0dd2333e53f935c51b43b520e238aae37053d31b
Reviewed-on: https://pdfium-review.googlesource.com/6972
Reviewed-by: Nicolás Peña <npm@chromium.org>
6 files changed