MLBEDSW-9163: Add support for TOSA NEGATE

* Add support for TOSA NEGATE with fewer than 4 dimensions.
* Add asserts to ensure that both IFMs have same data type where
  that's required.
* Add helper to create const tensors with a certain value.
* Update some other places to not trigger the new asserts.

Signed-off-by: Johan Gunnarsson <johan.gunnarsson@arm.com>
Change-Id: I8f572d3e754c3521e739bf146aa0a00358c758ec