Type[X] not compatible with metaclass of X

[JukkaL]

The second-to-last line should probably be accepted by mypy, but it currently generates an error because Type[A] isn't compatible with the metaclass of M:

from typing import Type

class M(type): pass
class A(metaclass=M): pass

a: Type[A] = A
m: M = a    # error, but should be okay
m2: M = A   # no error

[elazarg]

This was introduced by me in #2837: the metaclass lookup is performed on the wrong side.

[elazarg]

What's more, in the same PR I've made M compatible with Type[A], even though it is demonstrably unsafe... I would like to fix this too, but EnumMeta is relying on it.