The problem was the following:
There is a paragraph with an upper margin defined. Also, there
is a flyframe intersecting this upper margin. The desired behavior
is to reposition the parapgraph, such that it (including it's upper
margin) is located below the flyframe.

This patch increases the bounding rectangle of the paragraph by the
upper margin.

For compatibility, there is a compat-flag query. I re-used a related one.

Change-Id: I9dbc75e07e2ba0658fdbbfa9989be24a68660713
Reviewed-on: https://gerrit.libreoffice.org/52685Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>