[3.10] bpo-44559: [Enum] revert enum module to 3.9 (GH-27010)

* [Enum] revert enum module to 3.9
diff --git a/Lib/pstats.py b/Lib/pstats.py
index e77459d..0f93ae0 100644
--- a/Lib/pstats.py
+++ b/Lib/pstats.py
@@ -26,15 +26,14 @@
 import marshal
 import re
 
-from enum import StrEnum, _simple_enum
+from enum import Enum
 from functools import cmp_to_key
 from dataclasses import dataclass
 from typing import Dict
 
 __all__ = ["Stats", "SortKey", "FunctionProfile", "StatsProfile"]
 
-@_simple_enum(StrEnum)
-class SortKey:
+class SortKey(str, Enum):
     CALLS = 'calls', 'ncalls'
     CUMULATIVE = 'cumulative', 'cumtime'
     FILENAME = 'filename', 'module'