Test invisible-static elements upgrading when created with HTML parser

Invisible-static custom elements are still upgraded when they are
constructed through HTML parser. To make it clear, we are adding test
to confirm this behavior. This CL also make the previous test's
custom element constructor to not append a child to verify upgrades.

Previous change that defer upgrades of invisible="static" elements:
https://chromium-review.googlesource.com/c/chromium/src/+/1204373

Bug: 873057
Change-Id: If25afa4c1c77ecd70988d3d29cc5ab020247b8ea
Reviewed-on: https://chromium-review.googlesource.com/1235265
Commit-Queue: Rakina Zata Amni <rakina@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592710}
1 file changed