Make TypeQuery and TypeTranslator not traits (#9249)

This makes them usable by non-compiled plugins.
This fixes the user-blocking issue in #9001.

Author: msullivan

mypy/type_visitor.py

@@ -134,7 +134,6 @@ def visit_placeholder_type(self, t: PlaceholderType) -> T:
         pass
 
 
-@trait
 class TypeTranslator(TypeVisitor[Type]):
     """Identity type transformation.
 
@@ -242,7 +241,6 @@ def visit_type_alias_type(self, t: TypeAliasType) -> Type:
         pass
 
 
-@trait
 class TypeQuery(SyntheticTypeVisitor[T]):
     """Visitor for performing queries of types.