We always compared border width and other aspects only after that, Word
works with border weight according to their implementer notes.
So extend svx::frame::Style to be able to collapse borders using weights
and opt in for that from sw/ in case a compat mode (which is related to
tables, off by default and is set by the DOC/DOCX import) is set.
Change-Id: I1f682789302c88a0d326c6c0263ad3007441cb24
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/89052
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins