One of the thousands of redlines in the document contains a paragraph
that has a cross-ref bookmark on it.  At the end of the import the
redlines get hidden, i.e. copied and deleted from the body.

Because this redline starts in the middle of a paragraph, the
CrossRefBookmark on its last paragraph gets its position corrected
onto the middle of a paragraph, and it becomes unhappy and asserts.

Probably this can only happen in WW8 import, since other imports insert
the redline data into the redline area in the nodes array.

Change-Id: I5bfd94cacf9c2e76fd646728a123b3297b47c255
(cherry picked from commit 27384cdf)