runtime: allow stack split in body of closechan This gives more space during the call to runtime.lock.
runtime: allow stack split in body of closechan
This gives more space during the call to runtime.lock.

R=golang-dev, rsc
CC=golang-dev
https://codereview.appspot.com/11679043

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