Evaluate whether setting host memory limits is still necessary or beneficial

[randerzander]

We currently set host memory limits to the max available system memory.

As @beckernick suggests here, the many Dask improvements to GPU memory management may have made the host memory configuration unnecessary. We should evaluate if that's true.

[beckernick]

I agree, we should test this. My expectation is that the net effect of a variety changes makes this primarily relevant for conducting outsized workloads on small infrastructure. Given that isn't likely the default, we likely don't need to default to max system memory.