cmd/pprof: update vendored github.com/google/pprof

Pull in the latest published version of github.com/google/pprof
as part of #36905.

This adds the fmt.Println redundant newline fix from
google/pprof@f987b9c94b318d4bd026dcc7892f7f1fab6eadab.

Done with:

	go get -d github.com/google/pprof@latest
	go mod tidy
	go mod vendor

For #36905.
Fixes #49322.

Change-Id: Ia832766bba65a30c68407b73b33fefbe81438e65
Reviewed-on: https://go-review.googlesource.com/c/go/+/361294


Trust: Dmitri Shuralyov <dmitshur@golang.org>
Trust: Zvonimir Pavlinovic <zpavlinovic@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Zvonimir Pavlinovic <zpavlinovic@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Zvonimir Pavlinovic <zpavlinovic@google.com>