build: be verbose when running tests on Plan 9
build: be verbose when running tests on Plan 9

This is a temporary change to see how far the
builder gets when it times out.

LGTM=aram, 0intro
R=0intro, aram
CC=golang-codereviews, mischief
https://codereview.appspot.com/111400043

Committer: Aram Hăvărneanu <947f6c13826812af1df6a3fba06092a9b6c6b082@mgk.ro>

wesolows/golang,wesolows/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang,wesolows/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang,wesolows/golang-old