Revert "Don't compute histograms during phase 2 of rollups if >100k factor levels."
Revert "Don't compute histograms during phase 2 of rollups if >100k factor levels."

This reverts commit 1ff74853e5774819a1149845da673e7d2332c97d.

spennihana/h2o-3,YzPaul3/h2o-3,michalkurka/h2o-3,YzPaul3/h2o-3,h2oai/h2o-3,spennihana/h2o-3,kyoren/https-github.com-h2oai-h2o-3,pchmieli/h2o-3,jangorecki/h2o-3,kyoren/https-github.com-h2oai-h2o-3,jangorecki/h2o-3,h2oai/h2o-dev,madmax983/h2o-3,h2oai/h2o-3,kyoren/https-github.com-h2oai-h2o-3,spennihana/h2o-3,kyoren/https-github.com-h2oai-h2o-3,YzPaul3/h2o-3,jangorecki/h2o-3,madmax983/h2o-3,YzPaul3/h2o-3,h2oai/h2o-3,h2oai/h2o-dev,pchmieli/h2o-3,h2oai/h2o-3,mathemage/h2o-3,h2oai/h2o-dev,jangorecki/h2o-3,madmax983/h2o-3,michalkurka/h2o-3,mathemage/h2o-3,mathemage/h2o-3,kyoren/https-github.com-h2oai-h2o-3,h2oai/h2o-dev,kyoren/https-github.com-h2oai-h2o-3,pchmieli/h2o-3,kyoren/https-github.com-h2oai-h2o-3,jangorecki/h2o-3,michalkurka/h2o-3,mathemage/h2o-3,h2oai/h2o-dev,YzPaul3/h2o-3,madmax983/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,YzPaul3/h2o-3,mathemage/h2o-3,h2oai/h2o-dev,YzPaul3/h2o-3,madmax983/h2o-3,madmax983/h2o-3,pchmieli/h2o-3,mathemage/h2o-3,mathemage/h2o-3,spennihana/h2o-3,h2oai/h2o-3,jangorecki/h2o-3,spennihana/h2o-3,spennihana/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3,pchmieli/h2o-3,spennihana/h2o-3,pchmieli/h2o-3,jangorecki/h2o-3,h2oai/h2o-dev,h2oai/h2o-3,pchmieli/h2o-3,h2oai/h2o-3,madmax983/h2o-3