CL 21870 moved the entire cmd/pprof/internal directory to cmd/internal/pprof
for use by cmd/trace, but really cmd/trace only needed cmd/pprof/internal/profile,
which became cmd/internal/pprof/profile, and then internal/pprof/profile.

Move the rest back under cmd/pprof so that it is clear that no other code
is reaching into the guts of cmd/pprof. Just like functions should not be
exported unless necessary, internals should not be made visible to more
code than necessary.

Raúl Silvera noted after the commit of CL 21870 that only the profile package
should have moved, but there was no followup fix (until now).

Change-Id: I603f4dcb0616df1e5d5eb7372e6fccda57e05079
Reviewed-on: https://go-review.googlesource.com/32453
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Make internal pprof packages available to cmd/trace.
cmd/trace needs access to them to generate symbolized
svg profiles (create and serialize Profile struct).
And potentially generate svg programmatically instead
of invoking go tool pprof.

Change-Id: Iafd0c87ffdd4ddc081093be0b39761f19507907a
Reviewed-on: https://go-review.googlesource.com/21870
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Update #8798

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