fdo#78471: Write test for import of shared formulas from BIFF5.

Change-Id: I77fee109adf1c0decc6eb96cf2292f89fde1aceb
fdo#78471: Don't forget to record the ID of the last record for BIFF5.

Shared formula import code depends on this.

Change-Id: Iecb009252c56673df33e0d681de825911154903a