gh-108346: Fix failed benchmark in decimal (#108353)

Fix benchmark in decimal to work again after the int str conversion limits.

Modules/_decimal/tests/bench.py

@@ -7,6 +7,8 @@
 
 
 import time
+import sys
+from functools import wraps
 from test.support.import_helper import import_fresh_module
 
 C = import_fresh_module('decimal', fresh=['_decimal'])
@@ -64,7 +66,21 @@ def factorial(n, m):
     else:
         return factorial(n, (n+m)//2) * factorial((n+m)//2 + 1, m)
 
+# Fix failed test cases caused by CVE-2020-10735 patch.
+# See gh-95778 for details.
+def increase_int_max_str_digits(maxdigits):
+    def _increase_int_max_str_digits(func, maxdigits=maxdigits):
+        @wraps(func)
+        def wrapper(*args, **kwargs):
+            previous_int_limit = sys.get_int_max_str_digits()
+            sys.set_int_max_str_digits(maxdigits)
+            ans = func(*args, **kwargs)
+            sys.set_int_max_str_digits(previous_int_limit)
+            return ans
+        return wrapper
+    return _increase_int_max_str_digits
 
+def test_calc_pi():
     print("\n# ======================================================================")
     print("#                   Calculating pi, 10000 iterations")
     print("# ======================================================================\n")
@@ -86,7 +102,8 @@ def factorial(n, m):
             print("result: %s" % str(x))
             print("time: %fs\n" % (time.time()-start))
 
-
+@increase_int_max_str_digits(maxdigits=10000000)
+def test_factorial():
     print("\n# ======================================================================")
     print("#                               Factorial")
     print("# ======================================================================\n")
@@ -127,3 +144,7 @@ def factorial(n, m):
 
         if C is not None:
             assert(sx == sy)
+
+if __name__ == "__main__":
+    test_calc_pi()
+    test_factorial()