After the change in SERVER-82037, the memory needed for the iterators
is taken out of the sorter's maxMemoryUsageBytes. This means that some queries whose memory usage was earlier just near than the original limit will cross the new limit and spill, thereby regressing in performance. We should increase the default maxMemoryUsageBytes by the iterators max size (1 mb) to allow for the non-iterator memory usage to reach the original limit.