sweet/cmd/sweet: make TestSweetEndToEnd dump PGO logs

Right now if the PGO step fails, the logs printed by TestSweetEndToEnd
are pretty useless. Make it dump the PGO logs just like it dumps the
regular logs on failure

Change-Id: Id6530d967ff98dcb1d5b480b950bc9fcc51b08ea
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/600755
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
1 file changed