runtime: fix bug in tracebacks Need to correct for deferproc's extra 2 words of stack or in some cases (such as memory profiling) traceback can cause a crash. Also bulletproof the closure test.
runtime: fix bug in tracebacks
Need to correct for deferproc's extra 2 words of stack or in some
cases (such as memory profiling) traceback can cause a crash.
Also bulletproof the closure test.

R=rsc
CC=golang-dev
http://codereview.appspot.com/2138047

tav/go,tav/go,tav/go,tav/go,tav/go,tav/go,tav/go