Import the github.com/google/pprof and github.com/ianlancetaylor/demangle
packages, without modification.

Build the golang version of pprof from cmd/pprof/pprof.go
by importing the packages from src/cmd/vendot/github.com/google/pprof

The versions upstreamed are:

github.com/ianlancetaylor/demangle 4883227f66371e02c4948937d3e2be1664d9be38
github.com/google/pprof            7eb5ba977f28f2ad8dd5f6bb82cc9b454e123cdc

Update misc/nacl/testzip.proto for new tests.

Change-Id: I076584856491353607a3b98b67d0ca6838be50d6
Reviewed-on: https://go-review.googlesource.com/36798
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>