bpo-41811: create SortKey members using first given value (GH-22316) (GH-22325)

(cherry picked from commit ae0d2a33ec05aece939a959d36fcf1df1e210a08)

Co-authored-by: Ethan Furman <ethan@stoneleaf.us>
diff --git a/Lib/pstats.py b/Lib/pstats.py
index e781b91..0f93ae0 100644
--- a/Lib/pstats.py
+++ b/Lib/pstats.py
@@ -45,9 +45,9 @@
     TIME = 'time', 'tottime'
 
     def __new__(cls, *values):
-        obj = str.__new__(cls)
-
-        obj._value_ = values[0]
+        value = values[0]
+        obj = str.__new__(cls, value)
+        obj._value_ = value
         for other_value in values[1:]:
             cls._value2member_map_[other_value] = obj
         obj._all_values = values