Adjust existing WPT canvas layer tests shape sizes
This is done in preparation to a follow up change, where another
variant dimension will be added to validate context filters on layers.
Changing the drawing size will help making room for the new filter
effect.
Bug: 40249439
Change-Id: I162ac86e72c229dcd06a2020b401838013534d3a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5782996
Commit-Queue: Jean-Philippe Gravel jpgravel@chromium.org
Reviewed-by: Andres Ricardo Perez andresrperez@chromium.org
Cr-Commit-Position: refs/heads/main@{#1343544}