Add tests for all non-trivial functions in DenseIntSet
Add tests for all non-trivial functions in DenseIntSet

Zigazou/containers,hvr/containers,Zigazou/containers,shockkolate/containers,iu-parfunc/containers,ekmett/containers,ekmett/containers,shockkolate/containers,iu-parfunc/containers,Zigazou/containers,iu-parfunc/containers,shockkolate/containers,meiersi/psqueues-old,ekmett/containers,hvr/containers,hvr/containers