cmd/bent: fix overlapping output lines that broke "shortname:"

This fix also separates benchmark runs with blank lines, which looks
a whole darn lot better.

Change-Id: I39b4ef42c742b253ced4294872f9a07de022f136
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/462717
Reviewed-by: Michael Pratt <mpratt@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
1 file changed