bnc#863018 WW8 import: fix upper margin of multi-page floating table

A vert orient position was already handled in case a floating table was
imported as a TextFrame, but in case we didn't do that, the vert orient
position was simply lost.

Fix this by importing it as the upper margin of the table (assuming that
the position is relative from the anchor position).

(cherry picked from commit 3755c87d0426a499d4755e82d8fbc77caa240764)

Conflicts:
	sw/qa/extras/ww8import/ww8import.cxx

Change-Id: I3e96f3068605fd6313dfb3e55483e1bce6c063a5
Reviewed-on: https://gerrit.libreoffice.org/9487
Reviewed-by: Andras Timar <andras.timar@collabora.com>
Tested-by: Andras Timar <andras.timar@collabora.com>