time: Remove unnecessary call to Nanoseconds() in after().
time: Remove unnecessary call to Nanoseconds() in after().

R=golang-dev, bradfitz
CC=golang-dev
http://codereview.appspot.com/4528091

Committer: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

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