sweet: emit log filename in addition to log tail on error

This change makes Sweet emit the filename of the log most likely to
contain useful information in addition to the tail of that log on
failure.

Change-Id: I28e890f6108d56544efe6fba44225d7c42dc31e8
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/615575
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
1 file changed