[1.4.x] Fixed #17788 -- Added batch_size argument to qs.bulk_create()

The qs.bulk_create() method did not work with large batches together
with SQLite3. This commit adds a way to split the bulk into smaller
batches. The default batch size is unlimited except for SQLite3 where
the batch size is limited to 999 SQL parameters per batch.

Thanks to everybody who participated in the discussions at Trac.

Backpatch of 29132ebdef from master (with
documentation changes removed).

tests/regressiontests/queries/tests.py

@@ -1807,8 +1807,7 @@ class ConditionalTests(BaseQuerysetTest):
         # Test that the "in" lookup works with lists of 1000 items or more.
         Number.objects.all().delete()
         numbers = range(2500)
-        for num in numbers:
-            _ = Number.objects.create(num=num)
+        Number.objects.bulk_create(Number(num=num) for num in numbers)
         self.assertEqual(
             Number.objects.filter(num__in=numbers[:1000]).count(),
             1000