Create more intuitive behaviour when creating Tuples with duplicate types from smaller tuples

See title.

> Yes this is weird but I don't want to spend time on thinking about these corner cases, until we have a use case.
Tuple should be fast and correct for a "custom" definition of input spaces. Strange behavior in unused corner cases, should not bother us.

_Originally posted by @arBmind in https://github.com/basicpp17/basicpp17/diffs_