Remove flow control based on faulty assumption.
Remove flow control based on faulty assumption.

Now that the GREML derivatives code has been refactored, it's no longer
always true that AIM row-binning is faster when the number of threads is
less than or equal to the number of parameters.

mhunter1/OpenMx,mhunter1/OpenMx,mhunter1/OpenMx,mhunter1/OpenMx,mhunter1/OpenMx,jpritikin/OpenMx,jpritikin/OpenMx,jpritikin/OpenMx,jpritikin/OpenMx,mhunter1/OpenMx,jpritikin/OpenMx,jpritikin/OpenMx