For ordinary documents the SwTxtNode::MakeFrm() would set the
m_bFormatIgnoreStart/End flags of the RSID-only hints, but the document
loaded by Compare Document (and Merge Document) is special because it
is loaded, there are editing operations on it, but it has no layout,
so the assertions about these flags trigger.

(regression from 6db39dbd)

Change-Id: I8a6e02b68f22e609640adbe93ff194e4081d9856