[ASDisplayNode] Fix node is showing up as black box if wrapping an UIActivityIndicatorView (#3121)
[ASDisplayNode] Fix node is showing up as black box if wrapping an UIActivityIndicatorView (#3121)

* Set the node to not opaque if it’s wrapping an UIActivityIndicatorView

* Add check for subclass of UIVisualEffectView to see if the node needs to be opaque

maicki/AsyncDisplayKit,lappp9/AsyncDisplayKit,maicki/AsyncDisplayKit,flovouin/AsyncDisplayKit,lappp9/AsyncDisplayKit,flovouin/AsyncDisplayKit,flovouin/AsyncDisplayKit,lappp9/AsyncDisplayKit,lappp9/AsyncDisplayKit,flovouin/AsyncDisplayKit,maicki/AsyncDisplayKit,flovouin/AsyncDisplayKit,maicki/AsyncDisplayKit,maicki/AsyncDisplayKit