Remove or improve test "Unconnected natural lands and landuses"

[GerdP]

I fear I don't understand what this test is about. It collects ways whith keys landuse or natural but it will ignore all unconnected ways with key landuse and most of those with natural as they return true for method concernsArea()
So far I only found the tag natural=ridge which produces a useful warning.
Possible candidates like natural=tree_row or natural=cliff are explicitely excluded in the code. No idea why.
Typos like natural=woter will also produce a warning because concernsArea() returns false.

If preference validator.UnconnectedWays.way_way_distance is changed to a value > 0 (e.g. 5) this test will also produce "Other" messages about two landuse/natural areas which are very close (< 5m) but not connected. No idea where this is relevant.