Add prototype implementation of indirection chaining for affine copies
This PR adds support for scatter copies only and a particular format of the copy itself:
src<N1> --> unstructured_copy<N1-->N2> --> structured_copy<N2-->N3> --> dst<N3>
Restrictions:
- Only single level of indirections is allowed
- Only an unstructured copy can have a next indirection
- Only a structured copy can be used as a next indirection
Edited by apryakhin