tests: decode node output as UTF-8 explicitly
tests: decode node output as UTF-8 explicitly

In Python 3 we can't interpolate a bytestring into a Unicode string.

dhruvsinghal/watchman,kwlzn/watchman,wez/watchman,facebook/watchman,kwlzn/watchman,kwlzn/watchman,wez/watchman,dhruvsinghal/watchman,wez/watchman,dhruvsinghal/watchman,facebook/watchman,nodakai/watchman,dhruvsinghal/watchman,nodakai/watchman,nodakai/watchman,wez/watchman,nodakai/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,wez/watchman,dhruvsinghal/watchman,nodakai/watchman,dhruvsinghal/watchman,wez/watchman,facebook/watchman,kwlzn/watchman,facebook/watchman,facebook/watchman,wez/watchman,facebook/watchman,kwlzn/watchman,kwlzn/watchman,nodakai/watchman,wez/watchman,wez/watchman,nodakai/watchman,kwlzn/watchman,dhruvsinghal/watchman,dhruvsinghal/watchman,facebook/watchman,nodakai/watchman