cmd/pprof: add new Go version

[rsc]

A new Go version of pprof has replaced the original Perl script within Google (even for
non-Go programmers).

We should replace the public Go repo's copy of the Perl script with the new Go version.
This will make Perl not required to use pprof, which is especially useful on Windows.

[gopherbot]

Comment 1:

CL https://golang.org/cl/153750043 mentions this issue.

[gopherbot]

Comment 2:

CL https://golang.org/cl/153750044 mentions this issue.

[rsc]

Comment 3:

This issue was updated by revision c75f81f.

LGTM=bradfitz
R=crawshaw, bradfitz
CC=golang-codereviews
https://golang.org/cl/153750044

[rsc]

Comment 4:

This issue was updated by revision 8b5221a.

This is a new implementation of pprof,
written in Go instead of in Perl.
It was written primarily by Raul Silvera and
is in use for profiling programs of all languages
inside Google.
The internal structure is a bit package-heavy,
but it matches the copy used inside Google, and
since it is in an internal directory, we can make
changes to it later if we need to.
The only "new" file here is src/cmd/pprof/pprof.go,
which stitches together the Google pprof and the
Go command libraries for object file access.
I am explicitly NOT interested in style or review
comments on the rest of the files
(that is, src/cmd/pprof/internal/...).
Those are intended to stay as close to the Google
copies as possible, like we did with the pprof Perl script.
Still to do:
- Basic tests.
- Real command documentation.
- Hook up disassemblers.
LGTM=r
R=r, bradfitz, alex.brainman, dave
CC=golang-codereviews
https://golang.org/cl/153750043

[griesemer]

Comment 5:

Labels changed: added repo-main.

[rsc]

Comment 6:

I've done as much as I'm going to do this round.

Status changed to Fixed.