Change forkserver test to only run below 3.13.8 (pytorch#167361)

Change forkserver test to only run below 3.13.8 (pytorch#165667)

A multiprocessing bug is fixed in 3.13.8, see [https://docs.python.org/3.13/whatsnew/changelog.html](https://l.workplace.com/l.php?u=https%3A%2F%2Fdocs.python.org%2F3.13%2Fwhatsnew%2Fchangelog.html&h=AT0qUhHJq5c2UJvQaq9_MrSo0mVhwn1VOfq1nDQl2C1UOhDI80RMbzVayhG7LSAT1uYHKtkftKnBDwiGMhbw0YRvQLe5vwE01qejpPFautHvU3LXeOE1KChPykqz3qnCRzk7czu_iNzQ05shR4F1N_qYOzR5YxejA52ZZQ), [pytorchgh-126631](python/cpython#126631)

So this test will fail when we update to python 3.13.8
Pull Request resolved: pytorch#165667
Approved by: https://github.com/malfet

(cherry picked from commit d4a713c)

Co-authored-by: Shangdi Yu <[email protected]>

Author: pytorchbot

test/test_multiprocessing_spawn.py

@@ -265,6 +265,12 @@ def tearDown(self):
 )
 class ParallelForkServerPerfTest(TestCase):
 
+    @unittest.skipIf(
+        sys.version_info >= (3, 13, 8),
+        "Python 3.13.8+ changed forkserver module caching behavior",
+        # https://docs.python.org/3.13/whatsnew/changelog.html
+        # gh-126631
+    )
     def test_forkserver_perf(self):
 
         start_method = 'forkserver'