get_item_warehouse_projected_qty() called frappe.get_doc("Warehouse", ...)
inside the per-bin loop to walk up the warehouse hierarchy, re-fetching the
same parent warehouses over and over on sites with nested warehouses. Preload
the warehouse-to-parent mapping with a single query and walk it in-memory
instead, cutting the DB round-trips from O(bins * hierarchy depth) to one
query.
(cherry picked from commit 6beb3d2509)
c10b86d538