runtime: diagnose double wakeup on Note Double wakeup is prohibited by the Note interface and checked in lock_sema.c.
runtime: diagnose double wakeup on Note
Double wakeup is prohibited by the Note interface
and checked in lock_sema.c.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/6976054

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