runtime: fix bug in cpu profiler Number of lost samples was overcounted (never reset). Also remove unused variable (it's trivial to restore it for debugging if needed).
runtime: fix bug in cpu profiler
Number of lost samples was overcounted (never reset).
Also remove unused variable (it's trivial to restore it for debugging if needed).

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, rsc
https://codereview.appspot.com/96060043

pombredanne/go-deleteme,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,tv42/old-go,tv42/old-go,pombredanne/go-deleteme,tv42/old-go,pombredanne/go-deleteme,tv42/old-go,pombredanne/go-deleteme