fdo#81491 FILEOPEN DOCX Assert Fails while Deleting Para (FramePr)

SwXText::convertToTextFrame is called for a Para with FramePr.
convertToTextFrame in turn calls DelFullPara which throws an assert
as a few Bookmarks are still registered to the paragraph.

In  MarkManager::correctMarksAbsolute,  pMark->GetMarkPos().nNode.GetNode()
is checked if it is pOldNode, and then the Mark Position is shifted to aNewPos.
In the following condition pMark->GetOtherMarkPos().nNode.GetNode()
if it is the pOldNode, and still the Mark Position is changed.
However the Other Mark Position must be changed as now the Othe Mark is in pOldNode.

Change-Id: I4507f6b2906d33bc65c922fffe12db2110de651b
Reviewed-on: https://gerrit.libreoffice.org/10536Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>

sw/source/core/doc/docbm.cxx

@@ -584,7 +584,8 @@ namespace sw { namespace mark
             if (pMark->IsExpanded() &&
                 &pMark->GetOtherMarkPos().nNode.GetNode() == pOldNode)
             {
-                pMark->SetMarkPos(aNewPos);
+                // shift the OtherMark to aNewPos
+                pMark->SetOtherMarkPos(aNewPos);
                 bChangedOPos= true;
             }
             // illegal selection? collapse the mark and restore sorting later