Added support for testing whether a type is a Set. Also refactored TypeManager collection tests to use 1 common function.
Added support for testing whether a type is a Set. Also refactored TypeManager
collection tests to use 1 common function.

codespecs/daikon-dot-net-front-end,codespecs/daikon-dot-net-front-end,codespecs/daikon-dot-net-front-end,codespecs/daikon-dot-net-front-end