[text-box-trim] Retire text-box-edge propagation restriction

We added a restriction that the effective text-box-edge can be
propagated to its child only if the same node defines a non-initial
text-box-trim value when text-box-edge is not inherited.
But now the specification is updated[1] which marks text-box-edge as
inherited, and we no longer need this restriction.

This CL also removes
text-box-trim/text-box-trim-ignore-nested-text-box-edge.html
from the web-test. This test was replaces by
text-box-trim-not-ignore-nested-text-box-edge.html (each test
disagrees with the other) since [2], but for some reasons still stays
at the wpt codebase.

A follow-up will retire the EffectiveTextBoxEdge field.

[1] w3c/csswg-drafts#10904
[2] 288ee9d

Bug: 367766472, 374787320, 40254880
Change-Id: I789136ef54fa2d0c8b7a97b08caf1217512d10c2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6038647
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1388218}