Fix position on root node with RTL direction
Fix position on root node with RTL direction

Summary:
If the root node has a position and we have a RTL layout, that position must be like LTR direction. See #477.
Closes https://github.com/facebook/yoga/pull/502

Differential Revision: D4867144

Pulled By: emilsjolander

fbshipit-source-id: b5ad3d87e7054090da12d7665a3d1abe8496a548

facebook/litho,facebook/litho,facebook/litho,facebook/litho,facebook/litho,facebook/litho