runtime: revert init order changes

runtime: revert init order changes

First, remove the randomization of initialization order.

Then, revert to source code order instead of sorted package path order.

This restores the behavior that was in 1.12.

A larger change which will implement the suggestion in #31636 will
wait for 1.14. It's too complicated for 1.13 at this point (it has
tricky interactions with plugins).

Fixes #31636

Change-Id: I35b48e8cc21cf9f93c0973edd9193d2eac197628
Reviewed-on: https://go-review.googlesource.com/c/go/+/178297
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>