unix: remove /dev/ptyp* from device node tests on NetBSD

Follow up for CL 80615

The NetBSD 8.0 builders don't seem to have these device nodes either.
Just remove them entirely.

Change-Id: Ib729574ed119f9ec78b06124ba4a5d9bbc74bf4d
Reviewed-on: https://go-review.googlesource.com/81015
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

unix/dev_netbsd_test.go

@@ -23,8 +23,6 @@ func TestDevices(t *testing.T) {
 		// NetBSD 8.0
 		{"/dev/null", 2, 2},
 		{"/dev/zero", 2, 12},
-		{"/dev/ptyp0", 6, 0},
-		{"/dev/ptyp1", 6, 1},
 		{"/dev/random", 46, 0},
 		{"/dev/urandom", 46, 1},
 	}