ARM64 does this exact same thing, and in fact this is required on
Android 9, where Bionic now only allows lstat on 32-bit platforms
Folks are running into this when using Android on Chromebooks,
which are keeping AMD64 Android alive. So, we change the AMD64
behavior to model that of ARM64.

Change-Id: Id933cc22b42ab365c12980915557bdbf88661a4d
Reviewed-on: https://go-review.googlesource.com/c/153319
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>