path/filepath: do not restore original working directory twice in test

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://codereview.appspot.com/122910043
doc/go1.4.txt: implement monotonic clocks on windows

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://codereview.appspot.com/126760043
doc/go1.4.txt: add support for ALPN

LGTM=minux
R=r, agl, minux
CC=golang-codereviews
https://codereview.appspot.com/121340043