Update RESCALE testing to match no rank restrictions

Matches changes to the specification loosening the rank requirements for
the RESCALE operation.
Includes removing wrong rank testing for RESCALE, and increasing
conformance testing to rank 5

Signed-off-by: Eric Kunze <eric.kunze@arm.com>
Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>
Change-Id: I4e15d4bd8f448e1ec81d9a8bbcd231c286b64a30