cmd/bench: benchmark binary size and build time via bent

benchsize adds binary size benchmark results for each package in bent.
bent doesn't log these to stdout by default, we need to add -v for that.

It turns out that bent also has build time benchmarks that it doesn't
log without -v. So now we get those for free too.

Updates golang/go#57770.

Change-Id: I2b714a4f2e73842fe79d5d227a397efeca794d06
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/462718
Run-TryBot: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: David Chase <drchase@google.com>
diff --git a/cmd/bench/bent.go b/cmd/bench/bent.go
index bade299..2f87656 100644
--- a/cmd/bench/bent.go
+++ b/cmd/bench/bent.go
@@ -22,6 +22,7 @@
 [[Configurations]]
   Name = "{{.Name}}"
   Root = "{{.GOROOT}}"
+  AfterBuild = ["benchsize"]
 
 {{end -}}
 `))
@@ -111,6 +112,7 @@
 		"-N", "10",
 		"-C", confFile,
 		"-B", filepath.Join(dir, "benchmarks-50.toml"),
+		"-v",
 	)
 	cmd.Dir = dir
 	cmd.Stdout = os.Stdout