[PHP] + [Neko] haxe.ds.ObjectMap fails with key being a String or null

Hej,

This simple example works everywhere but fails on PHP : `spl_object_hash(): Argument #1 ($object) must be of type object, string given`
```haxe
class Main {
public static function main() {
var h = new haxe.ds.ObjectMap();
h.set( "foo" , true );
}
}
```

Thanks for reading me