The 1-minute test timeout seems a bit arbitrary. Use
internal/testenv.Command, which applies t.Deadline to subcommand.

For #67566.
Fixes #70124.

Change-Id: If84c96e353bdfaf02c9b123758198e031305ae32
Reviewed-on: https://go-review.googlesource.com/c/go/+/599056


LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
(cherry picked from commit 8c88f0c7)
Reviewed-on: https://go-review.googlesource.com/c/go/+/623595


Reviewed-by: Cherry Mui <cherryyz@google.com>