The code assumes that if it can move the cursor backward in line 2038,
that move can be "inverted" by moving the cursor forward after the
content has been moved - but if the cursor moved back a node, and the
moved content does not start with a SwTextNode, the cursor will move
forward skipping over the non-text nodes, so offsets in the aSaveBkmks
(and aSaveRedl, presumably) are going to be wrong.

Just don't use Move() if it leaves the current node.

Change-Id: I95278a10c14aeba9f76558486bb2712f6726dbcb