sweet: don't fetch large github repos for go-build benchmark if short

Currently the go-build benchmark fetches k8s and istio even if -short is
set. It won't build these repositories in this case, just fetch them. It
appears that fetching them is somewhat flaky, probably GitHub not liking
the fact that we're cloning such large repositories so often. (It's hard
to say why exactly it's failing, but every recently failure in the Sweet
integration test (#56958) is in exactly one of two places: cloning k8s
or istio from GitHub. It's also clear this cloning step is unnecessary
for this test.)

This CL modifies the harness' Get method to accept a struct (aligning
with the other harness methods) that now includes a Short parameter, the
same parameter passed to Build and Run. Now that "short" is plumbed down
into Get, we can skip cloning these repositories.

Fixes #56958.

Change-Id: Ia9e3749ac82608bc24a4a4791955d3a1f546faa1
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/498284
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
9 files changed