Fixed #33159 -- Reverted "Fixed #32970 -- Changed WhereNode.clone() to create a shallow copy of children."

This reverts commit e441847eca.

A shallow copy is not enough because querysets can be reused and
evaluated in nested nodes, which shouldn't mutate JOIN aliases.

Thanks Michal Čihař for the report.

tests/queries/tests.py

@@ -1663,6 +1663,12 @@ class Queries5Tests(TestCase):
             'bar %s'
         )
 
+    def test_queryset_reuse(self):
+        # Using querysets doesn't mutate aliases.
+        authors = Author.objects.filter(Q(name='a1') | Q(name='nonexistent'))
+        self.assertEqual(Ranking.objects.filter(author__in=authors).get(), self.rank3)
+        self.assertEqual(authors.count(), 1)
+
 
 class SelectRelatedTests(TestCase):
     def test_tickets_3045_3288(self):