Fixed #35665 -- Fixed a crash when passing an empty order_by to Window.

This also caused un-ordered sliced prefetches to crash as they rely on Window.

Regression in e16d0c176e that made OrderByList
piggy-back ExpressionList without porting the empty handling that the latter
provided.

Supporting explicit empty ordering on Window functions and slicing is arguably
a foot-gun design due to how backends will return undeterministic results but
this is a problem that requires a larger discussion.

Refs #35064.

Thanks Andrew Backer for the report and Mariusz for the review.

tests/expressions/tests.py

@@ -2315,11 +2315,6 @@ class ValueTests(TestCase):
         self.assertNotEqual(value, other_value)
         self.assertNotEqual(value, no_output_field)
 
-    def test_raise_empty_expressionlist(self):
-        msg = "ExpressionList requires at least one expression"
-        with self.assertRaisesMessage(ValueError, msg):
-            ExpressionList()
-
     def test_compile_unresolved(self):
         # This test might need to be revisited later on if #25425 is enforced.
         compiler = Time.objects.all().query.get_compiler(connection=connection)