tdf#160952 sw: ignore top margin only at page top, not e.g. table top

The bugdoc has a table at the top of the 2nd page and we ignored the top
margin inside the table cell (for the first paragraph), while this
doesn't happen in Word.

As mentioned at
<https://gerrit.libreoffice.org/c/core/+/167221/3#message-c03abf8e8e3cd20d49006058e6b3eb130585ff8f>,
the old code assumed "top of the page" for all frames not having a
previous frame, while that code was only tested with text frames
directly in the body frame of a page frame.

Fix the problem by limiting this "collapse upper spacing" behavior to
frames directly in body frames. This keeps the old bugdoc working, but
is meant to restore the old, wanted behavior in other cases like e.g. in
table cells.

If later it's discovered that upper spacing collapsing is wanted in
other contexts, those are best added on a case by case basis.

Change-Id: Ieb93facd8b2e7f6412fd20873c10ce6c8b775619
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/167631
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

0 files changed, 0 insertions, 0 deletions