WyC: put back broken code which allows constant sets to be interpreted as types.
WyC: put back broken code which allows constant sets to be interpreted as types.

Whiley/WhileyCompiler,hjwylde/whiley-compiler,hjwylde/whiley-compiler,hjwylde/whiley-compiler,hjwylde/whiley-compiler,hjwylde/whiley-compiler