http2/h2i: re-adjust build constraints

On Solaris, the MakeRaw and Restore functions of the
x/crypto/ssh/terminal package have been implemented, but on upcoming
platforms such as AIX, Fuchsia and Hurd still have no implementation.

Change-Id: I253249376802273f0160bf3ff1062a66e07b280f
Reviewed-on: https://go-review.googlesource.com/c/147677
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

http2/h2i/h2i.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !js,!nacl,!plan9,!solaris
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris windows
 
 /*
 The h2i command is an interactive HTTP/2 console.