I have found better approach, then longer wait.
See CL 134360043 for details.

««« original CL description
runtime/pprof: adjust cpuHogger so that tests pass on windows builders

LGTM=rsc
R=dvyukov, rsc
CC=golang-codereviews
https://golang.org/cl/140110043

»»»

LGTM=dave
R=golang-codereviews, dave, dvyukov
CC=golang-codereviews
https://golang.org/cl/133500043