cmd/link: put DYLD_INFO at beginning of LINKEDIT segment on darwin

cmd/link: put DYLD_INFO at beginning of LINKEDIT segment on darwin

Apparently, code signing requires DYLD_INFO tables are at the
beginning of the LINKEDIT segment. Put it there.

May fix #42507.

Change-Id: I1836e0f495719cf75f66d0831fe1544bbe3ff1a8
Reviewed-on: https://go-review.googlesource.com/c/go/+/269377
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>