Uncomment two tests and xfail them instead, to reduce the chance of code rot

[wyattscarpenter]

These had already broken slightly as fixtures are pyi files and not py files, now. I also fixed that.

This is a sort of curious change, as these used to be -skipped, anyway, before the previous commit commented them out.

[JelleZijlstra]

We might still get PEP 718, I guess. Do we get any value out of keeping this xfailed test around?

[ilevkivskyi]

Oh wow, I somehow completely missed this PEP, I think this is great idea. IMO it is more pythonic to have

x = foo[int](...)

than

x: some_type[int] = foo(...)

for local variables. (I mean there is no such thing as a local variable in Python, there are just names).