Currently, when loading half scans of certain type of progressive jpegs, the last
scan is not displayed correctly. We provide a fix and a test.

Bug: 1156120
Change-Id: If6ab87bda49fddf28bdf2062fc155ac85f9290c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2577498
Commit-Queue: Moritz Firsching <firsching@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Auto-Submit: Moritz Firsching <firsching@google.com>
Cr-Commit-Position: refs/heads/master@{#835634}