Correct the pipe and pipe2 implementations by using the correct RSP offsets,
used to store and return the file descriptor array.

Fix setNonblock by using the correct immediate value for O_NONBLOCK and
replace EOR (exclusive OR) with ORR.

Also correct the write1 implementation, which has a uintptr value for the fd
argument.

Change-Id: Ibca77af44b649e8bb330ca54f9c36a7a8b0f9cea
Reviewed-on: https://go-review.googlesource.com/c/go/+/212765
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>