Non-mandatory tour scheduling model runtime gets worse as more multiprocess cores are added

As seen by @i-am-sijia in https://github.com/ActivitySim/sandag-abm3-example/issues/9#issuecomment-2236832539 and  @dhensle in https://github.com/ActivitySim/sandag-abm3-example/issues/9#issuecomment-2231432513, the non-mandatory tour scheduling model runtime gets worse as more multiprocess cores are added. This is not seen in the sharrow on version of the code, only in the legacy code.