Remove all uses of findNodeHandle #4183

tags aren't supported by Fabric. The main function that deals with tags is findNodeHandle(). Facebook is replacing all tags with instances. We need to do the same in our overrides.

There are multiple places we're doing this:
Libraries\Components\Flyout\Flyout.windows.tsx:42: const newtarget: number | null = findNodeHandle(nextProps.target as
Libraries\Components\Popup\Popup.windows.tsx:42: const newTarget: number | null = findNodeHandle(nextProps.target as
Libraries\Components\ScrollView\ScrollView.windows.js:752: return ReactNative.findNodeHandle(this._scrollViewRef);
Libraries\Components\ScrollView\ScrollView.windows.js:756: return ReactNative.findNodeHandle(this._innerViewRef);
Libraries\Components\TextInput\TextInput.windows.js:825: ReactNative.findNodeHandle(this._inputRef)
Libraries\Components\TextInput\TextInput.windows.js:837: const tag = ReactNative.findNodeHandle(this._inputRef);
Libraries\Components\TextInput\TextInput.windows.js:853: const tag = ReactNative.findNodeHandle(this._inputRef);
Libraries\Lists\VirtualizedList.windows.js:444: return ReactNative.findNodeHandle(this._scrollRef);