* Add explicit copy stage for batch_matmul(x, x) case
* do copy in relay strategy to avoid dup
* add copy to dense op and schedules
* black
* add batch_matmul test
* add dense test
* fix cuda int8 dense test
* remove need_copy flag
* do not use tag to decide if tensors are same
* rename to copy_if_identical and add comment
* black
* one more fix missed
* add length check on input tensors
* one more length check
* fix variable name
masahi
d12e7259c2