__slots__ in list.pyi caused several failures

Author: sobolevn

test-data/unit/check-classes.test

@@ -1000,11 +1000,6 @@ class C(P):
     x = ['a']  # E: List item 0 has incompatible type "str"; expected "int"
 [builtins fixtures/list.pyi]
 
-[case testClassSlotsAttributeWithTypeInference]
-class P:
-    __slots__ = []
-[builtins fixtures/list.pyi]
-
 [case testAccessingGenericClassAttribute]
 from typing import Generic, TypeVar
 T = TypeVar('T')

test-data/unit/fixtures/list.pyi

@@ -1,11 +1,10 @@
 # Builtins stub used in list-related test cases.
 
-from typing import TypeVar, Generic, Iterable, Iterator, Union, Sequence, overload
+from typing import TypeVar, Generic, Iterable, Iterator, Sequence, overload
 
 T = TypeVar('T')
 
 class object:
-    __slots__: Union['str', Iterable['str']]
     def __init__(self) -> None: pass
 
 class type: pass