Updating to commit e41fb7133e7ebb84ba6af2f6443032c728db26d3
from github.com/google/pprof

This fixes #19322

Change-Id: Ia1c008a09f46ed19ef176046e38868eacb715682
Reviewed-on: https://go-review.googlesource.com/37617Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>