[3.14] gh-149285: Increase recursion depth for test_xml_etree from 150k to 500k (GH-149286) (#149287)

(cherry picked from commit b1d6231)

Co-authored-by: Zanie Blue <contact@zanie.dev>

Author: miss-islington

Lib/test/test_xml_etree.py

@@ -3105,7 +3105,7 @@ def test_deeply_nested_deepcopy(self):
         # This should raise a RecursionError and not crash.
         # See https://github.com/python/cpython/issues/148801.
         root = cur = ET.Element('s')
-        for _ in range(150_000):
+        for _ in range(500_000):
             cur = ET.SubElement(cur, 'u')
         with support.infinite_recursion():
             with self.assertRaises(RecursionError):