net: enable cgo test on solaris

Change-Id: I4ade27469d82839b4396e1a88465dddc6b31d578
Reviewed-on: https://go-review.googlesource.com/9838Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>

src/net/cgo_unix_test.go

@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // +build cgo,!netgo
-// +build darwin dragonfly freebsd linux netbsd openbsd
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package net