* [CUBLAS] Add cuBLAS as a Relay partitioning target (BYOC)
This PR adds a partitioning pass for cuBLAS so that
supported Relay patterns can be offloaded to cuBLAS.
This initial commit only adds offloading support
for nn.matmul.
Although cuBLAS is already enabled in TVM by using
strategy selection in TE, by exposing it explicitly
as a Relay partitioning target we can more precisely
describe how to execute a model in Relay. This is
desirable particularly in the Collage effort to
improve multi-backend graph partitioning.
* Refactor to remove boilerplate
Matthew Barrett
b2a0e1d274