Previously, cover printed directives (//go: comments) near the top of
the file unless they were in doc comments. However, directives
frequently apply to specific definitions, and they are not written in
doc comments to prevent godoc from printing them. Moving all
directives to the top of the file affected semantics of tests.

With this change, directives are kept together with the following
top-level declarations. Only directives that occur after all top-level
declarations are moved.

Fixes #22022

Change-Id: Ic5c61c4d3969996e4ed5abccba0989163789254c
Reviewed-on: https://go-review.googlesource.com/69630
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

TBR=rsc

Change-Id: I6ec69013027213c5e7adedd2edb89dea6af876d9
Reviewed-on: https://go-review.googlesource.com/9563
Reviewed-by: Rob Pike <r@golang.org>

This required dealing with the ill-advised split of the profile code
into a separate package. I just copied it over unchanged. The package
does not deserve to be in the standard repository. We can cope
with the duplication.

Also update the go command to know about the new location.

Fixes #10528.

Change-Id: I05170ef3663326d57b9c18888d01163acd9256b6
Reviewed-on: https://go-review.googlesource.com/9560
Reviewed-by: Russ Cox <rsc@golang.org>