1.6 changes, courtesy Alex Miller
Fix a bug on persistent maps/sets when conjing on a collision node which underwent a transient modification.

Signed-off-by: Stuart Halloway <stu@thinkrelevance.com>
CLJ-1285: add generative test for conj/disj/persistent/transient on sets

Signed-off-by: Stuart Halloway <stu@thinkrelevance.com>