Group#replace and updateZ order issue

[hightopo]

https://github.com/photonstorm/phaser/blob/dev/src/core/Group.js#L689
In Group's replace method, when removeChild is invoked, newChild.parent will become undefined, so i think we should save parent to variable before remvoeChild, then parent.updateZ()

    if (newChild.parent !== undefined)
    {
        newChild.events.onRemovedFromGroup$dispatch(newChild, this);
        newChild.parent.removeChild(newChild);

        if (newChild.parent instanceof Phaser.Group)
        {
            newChild.parent.updateZ();
        }
    }

[pnstickne]

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