runtime: revert Apple libc atfork workaround
Revert CL 451735 (
1f4394a0c926), which fixed #33565 and #56784
but also introduced #57263.
I have a different fix to apply instead. Since the first fix was
never backported, it will be easiest to backport the new fix
if the new fix is done in a separate CL from the revert.
Change-Id: I6c8ea3a46e542ee4702675bbc058e29ccd2723e0
Reviewed-on: https://go-review.googlesource.com/c/go/+/459175
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>