Fix some test cases

Author: msullivan

test-data/unit/check-isinstance.test

@@ -2077,9 +2077,7 @@ class A: pass
 
 def foo1(x: Union[A, str, None]) -> None:
     if x is None:
-        # Since None is a subtype of all types in no-strict-optional,
-        # we can't really narrow the type here
-        reveal_type(x)      # E: Revealed type is 'Union[__main__.A, builtins.str, None]'
+        reveal_type(x)      # E: Revealed type is 'None'
     elif isinstance(x, A):
         # Note that Union[None, A] == A in no-strict-optional
         reveal_type(x)      # E: Revealed type is '__main__.A'
@@ -2088,12 +2086,12 @@ def foo1(x: Union[A, str, None]) -> None:
 
 def foo2(x: Optional[str]) -> None:
     if x is None:
-        reveal_type(x)      # E: Revealed type is 'Union[builtins.str, None]'
+        reveal_type(x)      # E: Revealed type is 'None'
     elif isinstance(x, A):
         # Mypy should, however, be able to skip impossible cases
         reveal_type(x)
     else:
-        reveal_type(x)      # E: Revealed type is 'Union[builtins.str, None]'
+        reveal_type(x)      # E: Revealed type is 'builtins.str'
 [builtins fixtures/isinstance.pyi]
 
 [case testNoneCheckDoesNotNarrowWhenUsingTypeVars]
@@ -2153,7 +2151,7 @@ def bar(x: Union[List[str], List[int], None]) -> None:
 from typing import Union, Optional, List
 
 # This test is the same as the one above, except for strict-optional.
-# It isn't testing anything explicitly and mostly exists for the sake 
+# It isn't testing anything explicitly and mostly exists for the sake
 # of completeness.
 
 def foo(x: Optional[List[str]]) -> None:
@@ -2166,4 +2164,3 @@ def bar(x: Union[List[str], List[int], None]) -> None:
     assert isinstance(x, list)
     reveal_type(x)                  # E: Revealed type is 'Union[builtins.list[builtins.str], builtins.list[builtins.int]]'
 [builtins fixtures/isinstancelist.pyi]
-

test-data/unit/check-tuples.test

@@ -1099,7 +1099,7 @@ possibles: Tuple[int, Tuple[A]]
 x: Optional[Tuple[B]]
 
 if x in possibles:
-    reveal_type(x) # E: Revealed type is 'Union[Tuple[__main__.B], None]'
+    reveal_type(x) # E: Revealed type is 'Tuple[__main__.B]'
 else:
     reveal_type(x) # E: Revealed type is 'Union[Tuple[__main__.B], None]'
 

test-data/unit/check-unreachable-code.test

@@ -599,7 +599,7 @@ class Child(Parent):
     def foo(self) -> int:
         reveal_type(self)       # E: Revealed type is '__main__.Child'
         if self is None:
-            reveal_type(self)   # E: Revealed type is '__main__.Child'
+            reveal_type(self)   # E: Revealed type is 'None'
             return None
         reveal_type(self)       # E: Revealed type is '__main__.Child'
         return 3