Revert "runtime: set stackguard1 on extra M g0"

Revert "runtime: set stackguard1 on extra M g0"

This reverts CL 527056.

CL 525455 breaks darwin, alpine, and android. This CL must be reverted
in order to revert that CL.

For #62440.

Change-Id: I4e1b16e384b475a605e0214ca36c918d50faa22c
Reviewed-on: https://go-review.googlesource.com/c/go/+/527316
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>