[Go] Don't convert arrays to pointers if there is a "gotype" typemap entry.

Fixes #749

Examples/test-suite/go/go_inout_runme.go

@@ -54,4 +54,8 @@ func main() {
 	c1 := go_inout.NewC1()
 	c2.M2(c1)
 	c2.M2(nil)
+
+	if !go_inout.Strings([]string{"1", "2"}) {
+		panic("Strings failed")
+	}
 }