syscall: don't use faccessat2 on android

syscall: don't use faccessat2 on android

The Android seccomp policy does not allow faccessat2, so attempting to
use it results in a SIGSYS. Avoid it and go straight to the fallback.

Fixes #57393.

Change-Id: I8d4e12a6f46cea5642d3b5b5a02c682529882f29
Reviewed-on: https://go-review.googlesource.com/c/go/+/458495
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Changkun Ou <mail@changkun.de>
Run-TryBot: Michael Pratt <mpratt@google.com>