run.bash: fix linux/arm build
run.bash: fix linux/arm build

Revert to the shell builtin to avoid hosts that do not have /usr/bin/time.

R=golang-dev, iant
CC=golang-dev
http://codereview.appspot.com/6848054

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang