DL: Convert sizing tests to use rendersubtree and content-size

Note there are some changes (contain-size* references)
and some weird results in get-bounding-client-rect-block-layout.html

Bug: 1000702
Change-Id: I028a00de6c9e6700c1ce1a2e3f05c6037958777b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1792221
Reviewed-by: vmpstr <[email protected]>
Commit-Queue: Rakina Zata Amni <[email protected]>
Cr-Commit-Position: refs/heads/master@{#695902}
44 files changed