time: during short test, do not bother tickers take longer than expected
time: during short test, do not bother tickers take longer than expected

R=golang-dev, bradfitz
CC=golang-dev
http://codereview.appspot.com/5752058

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