Revert "cmd/link: default to external linking with cgo std packages"

Revert "cmd/link: default to external linking with cgo std packages"

This reverts CL 470298.

Reason for revert: causes issues with Google internal testing.

Updates #58619.
Updates #58620.

Change-Id: Ic6601820ba8758ef96b71e32d9ffc549c36d5c98
Reviewed-on: https://go-review.googlesource.com/c/go/+/470835
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>