This is a bad idea as the function is sometimes used to check if a
SwFrameFormat has been deleted, which can happen in Undo, and for
SwCallMouseEvent before commit 32403675

Replace with ContainsFormat() and IsAlive(), and don't require a
non-const SwFrameFormat parameter.

Change-Id: I87ede94dfbfe7f6985f13faab4c156015c3a5fc0