[ChromeDriver] Update test_partially_visible_does_not_scroll expectations.

Bug: chromedriver:2852
Change-Id: I53780d13968dfaca34628e203e10338175edb96e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1592063
Reviewed-by: John Chen <johnchen@chromium.org>
Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: Rohan Pavone <rohpavone@chromium.org>
Cr-Commit-Position: refs/heads/master@{#655691}