[line-clamp] Allow displacing entire lines by the line-clamp ellipsis

The spec text for `block-ellipsis` says that if there is no break
opportunity in the text that would allow the text and the ellipsis to
fit in the line, the entire contents of the line must be displaced,
being replaced with the ellipsis. In that case, when line-breaking the
line, we rewind to the initial position without marking it as an empty
line.

Bug: 40336192
Change-Id: I5f13f61e5f1a586de9451fecd96500eedd5a1628
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6395136
Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Andreu Botella <abotella@igalia.com>
Cr-Commit-Position: refs/heads/main@{#1442000}