Check the output shape of broadcast operations

For an operation that performs broadcast the
output shape size must be the maximum of the input shape
sizes in each dimension.

Additionally, the input dimension size must be 1 whenever
an input shape does not match the output shape size
in a dimension.

Signed-off-by: Dominic Symes <dominic.symes@arm.com>
Change-Id: I89492f4ef22da76f84f12e720c79634ea42545bc