Simpler model. Based on single-step fitting.
Addition model for nested loop equi join
New join model by JW
Added model w/o less 100K per instance observed (Cluster + TableScan)

This model does not use datapoints which had less than 100k rows per instance
to work on. As instances become smaller than 100k rows, they tend to exhibit
random runtime behavior and are therefore no longer subject to our model. Thus,
they have been excluded. This lead to a far better matching fitting for those
tasks.
Cap for RadixJoin is 200 now