gh-143544: Use support.swap_attr in re-entrant JSONDecodeError test

Author: VanshAgarwal24036

Lib/test/test_json/test_fail.py

@@ -1,4 +1,6 @@
 from test.test_json import PyTest, CTest
+from test import support
+import json
 
 # 2007-10-05
 JSONDOCS = [
@@ -236,6 +238,7 @@ def test_linecol(self):
                              'Expecting value: line %s column %d (char %d)' %
                              (line, col, idx))
 
+
     def test_reentrant_jsondecodeerror_does_not_crash(self):
         # gh-143544