sweet: add GOMAXPROCS suffix to benchmark names

This change adds the GOMAXPROCS suffix to benchmark names the same way
that `go test` does.

Change-Id: I3ae168620de716c0aa8b642d099ba5308c54f48b
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/580837
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
4 files changed