Fix test: testUnionOrSyntaxWithinRuntimeContextNotAllowed

Author: davidfstr

test-data/unit/check-union-or-syntax.test

@@ -106,7 +106,8 @@ b: X  # E: Variable "__main__.X" is not valid as a type \
 # flags: --python-version 3.9
 from __future__ import annotations
 from typing import List
-T = int | str  # E: Invalid type alias: expression is not a valid type
+T = int | str  # E: Invalid type alias: expression is not a valid type \
+               # E: Unsupported left operand type for | ("type[int]")
 class C(List[int | str]):  # E: Type expected within [...] \
                            # E: Invalid base class "List"
     pass