This patch rebaselines 1px differences in the baseline
positioning when the 'vertical-aling' property is used.

Legacy computes the baseline position in multiple steps,
while NG computes in single function. This difference
causes slight rounding differences.

TBR=atoti@chromium.org
NOTRY=true

Bug: 636993
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: Ia2adec046f2ac13dfb4d479e8ffa56cb4a3bd040
Reviewed-on: https://chromium-review.googlesource.com/1107860
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568835}