Fix several tests on Python 3.11 (#13259)

As a result of python/cpython#94948
we started to fail these tests on Python 3.11b5

Author: hauntsaninja

test-data/unit/check-python38.test

@@ -210,7 +210,7 @@ h(arg=0)  # E: Unexpected keyword argument "arg" for "h"
 i(arg=0)  # E: Unexpected keyword argument "arg"
 
 [case testWalrus]
-# flags: --strict-optional
+# flags: --strict-optional --python-version 3.8
 from typing import NamedTuple, Optional, List
 from typing_extensions import Final
 
@@ -385,6 +385,7 @@ reveal_type(z2)  # E: Name "z2" is not defined  # N: Revealed type is "Any"
 [builtins fixtures/isinstancelist.pyi]
 
 [case testWalrusConditionalTypeBinder]
+# flags: --python-version 3.8
 from typing import Union
 from typing_extensions import Literal
 
@@ -405,7 +406,7 @@ else:
 [builtins fixtures/property.pyi]
 
 [case testWalrusConditionalTypeCheck]
-# flags: --strict-optional
+# flags: --strict-optional --python-version 3.8
 from typing import Optional
 
 maybe_str: Optional[str]
@@ -421,6 +422,7 @@ reveal_type(maybe_str)  # N: Revealed type is "Union[builtins.str, None]"
 [builtins fixtures/bool.pyi]
 
 [case testWalrusConditionalTypeCheck2]
+# flags: --python-version 3.8
 from typing import Optional
 
 maybe_str: Optional[str]
@@ -436,6 +438,7 @@ reveal_type(maybe_str)  # N: Revealed type is "Union[builtins.str, None]"
 [builtins fixtures/bool.pyi]
 
 [case testWalrusPartialTypes]
+# flags: --python-version 3.8
 from typing import List
 
 def check_partial_list() -> None:
@@ -452,7 +455,7 @@ def check_partial_list() -> None:
 [builtins fixtures/list.pyi]
 
 [case testWalrusAssignmentAndConditionScopeForLiteral]
-# flags: --warn-unreachable
+# flags: --warn-unreachable --python-version 3.8
 
 if (x := 0):
     reveal_type(x)  # E: Statement is unreachable
@@ -462,7 +465,7 @@ else:
 reveal_type(x)  # N: Revealed type is "builtins.int"
 
 [case testWalrusAssignmentAndConditionScopeForProperty]
-# flags: --warn-unreachable
+# flags: --warn-unreachable --python-version 3.8
 
 from typing_extensions import Literal
 
@@ -490,7 +493,7 @@ reveal_type(y)  # N: Revealed type is "Literal[False]"
 [builtins fixtures/property.pyi]
 
 [case testWalrusAssignmentAndConditionScopeForFunction]
-# flags: --warn-unreachable
+# flags: --warn-unreachable --python-version 3.8
 
 from typing_extensions import Literal
 
@@ -523,6 +526,7 @@ reveal_type(z)  # N: Revealed type is "Literal[False]"
 [builtins fixtures/tuple.pyi]
 
 [case testWalrusExpr]
+# flags: --python-version 3.8
 def func() -> None:
     foo = Foo()
     if x := foo.x:
@@ -533,6 +537,7 @@ class Foo:
         self.x = 123
 
 [case testWalrusTypeGuard]
+# flags: --python-version 3.8
 from typing_extensions import TypeGuard
 def is_float(a: object) -> TypeGuard[float]: pass
 def main(a: object) -> None:
@@ -542,6 +547,7 @@ def main(a: object) -> None:
 [builtins fixtures/tuple.pyi]
 
 [case testWalrusRedefined]
+# flags: --python-version 3.8
 def foo() -> None:
     x = 0
     [x := x + y for y in [1, 2, 3]]