Test: cts-scheduler: add test for "primitive with group with clone"

The essential elements of this test are:

• A primitive is colocated with a group colocated with a clone
• The clone is assigned first
• The clone can't run on all nodes (clone-max=3 with 5 nodes)
• The primitive has a finite location constraint preferring node5

With the current code, the primitive's location preference is wrongly ignored,
and the clone instances get assigned to node2, node3, and node4.