Fix decorated methods with self-types in protocols

[ilevkivskyi]

Fixes #19482

The regression is caused by overlap of three problems (directly or indirectly):

• Using mx.original_type instead of mx.self_type for expanding (not otherwise bound) self-types.
• Having a weird special case for ... vs self-types in constraint inference.
• Not refreshing type variable ids during protocol subtype checks (hack needed for technical reasons).

I fix the first one, and limit the blast radius of the second one.

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

steam.py (https://github.com/Gobot1234/steam.py)
- steam/chat.py:402: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Chat[ChatMessageT, ClanT, GroupT]]"; expected "type[Self]"  [arg-type]
+ steam/chat.py:402: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Chat[ChatMessageT, ClanT, GroupT]]"; expected "type[Never]"  [arg-type]
- steam/chat.py:589: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Self]"  [arg-type]
+ steam/chat.py:589: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Never]"  [arg-type]
- steam/chat.py:608: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Self]"  [arg-type]
+ steam/chat.py:608: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Never]"  [arg-type]
- steam/chat.py:643: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Self]"  [arg-type]
+ steam/chat.py:643: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Never]"  [arg-type]
- steam/chat.py:688: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Self]"  [arg-type]
+ steam/chat.py:688: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Never]"  [arg-type]
- steam/chat.py:696: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Self]"  [arg-type]
+ steam/chat.py:696: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Never]"  [arg-type]
- steam/chat.py:869: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Self]"  [arg-type]
+ steam/chat.py:869: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ChatGroup[MemberT, ChatT, ChatGroupTypeT]]"; expected "type[Never]"  [arg-type]
+ steam/state.py:1470: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[GroupChannel]"; expected "type[Never]"  [arg-type]
+ steam/state.py:1470: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ClanChannel]"; expected "type[Never]"  [arg-type]
+ steam/state.py:1509: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[GroupChannel]"; expected "type[Never]"  [arg-type]
+ steam/state.py:1509: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[ClanChannel]"; expected "type[Never]"  [arg-type]
+ steam/state.py:2277: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Commentable]"; expected "type[Never]"  [arg-type]
+ steam/state.py:2289: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Commentable]"; expected "type[Never]"  [arg-type]
+ steam/state.py:2304: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[OwnerT]"; expected "type[Never]"  [arg-type]
+ steam/state.py:2328: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Commentable]"; expected "type[Never]"  [arg-type]
+ steam/state.py:2339: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Commentable]"; expected "type[Never]"  [arg-type]
+ steam/state.py:2426: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Awardable[int]]"; expected "type[Never]"  [arg-type]
- steam/state.py:2439: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Awardable[int]]"; expected "type[type[Awardable[int]]]"  [arg-type]
+ steam/state.py:2439: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Awardable[int]]"; expected "type[Never]"  [arg-type]

[ilevkivskyi]

The mypy_primer looks correct. We never supported "capturing" generic callables in an instance type (this would require existential types or similar), except for a hack that only works with paramspecs.