fdo#73655: Don't adjust formula tokens on non-top shared formula cells.

Only adjust tokens for non-shared formula cells and shared formuls cells
that are the top of their respective shared groups.

Change-Id: I9cd57653602c97504a802001947a28c4d03368a5
fdo#73655: Write unit test for this.

Change-Id: I0409e3c482d8a833672f41b1398333e5181847af