net: android no longer supports unix/unixgram

I cannot find any documentation for this, but these tests no longer run
on the device I have since upgrading to Android L. Presumably it still
works for root, but standard Android programs to not have root access.

Change-Id: I001c8fb5ce22f9ff8d7433f881d0dccbf6ab969d
Reviewed-on: https://go-review.googlesource.com/16056
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

src/net/platform_test.go

@@ -32,7 +32,7 @@ func testableNetwork(network string) bool {
 		}
 	case "unix", "unixgram":
 		switch runtime.GOOS {
-		case "nacl", "plan9", "windows":
+		case "android", "nacl", "plan9", "windows":
 			return false
 		}
 		// iOS does not support unix, unixgram.