Improve generics on some collection matchers.

The following classes are no longer parameterized as they don't care what is in
the collection they match:
- IsCollectionWithSize
- IsIterableWithSize
- IsMapWithSize
- IsEmptyCollection
- IsEmptyIterable

--HG--
extra : amend_source : 16d1096955ea69a58de1a57978038a594533f6a4