* Batch benchmarks together with `*` notation.

* Fix short structopt conflict

* Return error if `batches` is empty

* Move fast benchmarks macro into `frame_benchmarking` (#5445)

* Move macro into `frame_benchmarking`

* Update docs

* Extra line

* Return error if `batches` is empty

Co-authored-by: Shawn Tabrizi <[email protected]>