switch on Dynamic

Hej,

First of all, I know using Dynamic is really kamikaze thing, but I just want to know if it's a switch bug or if it's definitivly like "we don't support Dynamic anymore :rofl:"

Consider this example :
```haxe
enum Foo{
FBar1;
FBar2;
}
class Test {
static function main() {
var o : Dynamic = "test";
switch o {
case null:
trace( "null case" );
case FBar1:
trace( "Fbar 1");
case FBar2:
trace( "Fbar 2");
case _:
trace( o );
}
}
}
```
Here it doesn't trace anything, but if we comment the 2 cases FBar1 and FBar2, it do trace "test" as expected : https://try.haxe.org/#d0C0Bd50