MLBEDSW-10540: Implement local allocation of IO tensors

This changes address allocation of IO tensors to happen per
command stream, instead of globally for all command streams.
It means each command stream will have its own address space for
the IO tensors. The linear allocator is still used.

This only affects the --separate-io-regions option.

Signed-off-by: Johan Gunnarsson <johan.gunnarsson@arm.com>
Change-Id: Ifad3a99254b760e28b4ab4b729e7cc050537f496