If an arm is nearly parallel to the bed then that tower's carriage may
have a velocity up to 3 times greater than the toolhead's maximum
velocity (relative to the print). Take that into account when
calculating the stepper's maximum halt velocity.
This fixes some rare "No next step" shutdowns on delta printers.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
390d549c0c