TestFifoEOF fails on android because the mkfifo syscall is not allowed:

--- FAIL: TestFifoEOF (0.00s)
    fifo_test.go:39: permission denied

Change-Id: I007ff359831525add39cec34de4b3d3cd3adb047
Reviewed-on: https://go-review.googlesource.com/118815
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>