RFR: Disable "super" partial heuristics, leaving only LRU/Generational

[Aleksey Shipilev]

I think generic "partial" heuristics outlived its purpose as the proving ground for minor
collections support. Now that we have more advanced heuristics like LRU/Generational, we can stop
using the generic one:
  http://cr.openjdk.java.net/~shade/shenandoah/partial-remove-super/webrev.01/

The generic one is not tuned anyway, and only wastes testing cycles. Further work may add more
sub-classes that employ other partial cset selection strategies.

Testing: hotspot_gc_shenandoah

Thanks,
-Aleksey