Test `YogaNode#getLayoutDirection()`
Test `YogaNode#getLayoutDirection()`

Summary:
@public

Previously untested. Allows us to ship with more confidence

Reviewed By: SidharthGuglani

Differential Revision: D13534350

fbshipit-source-id: a2e7577befdeeb7a27148e16624eeb7a347efd87

facebook/yoga,facebook/yoga,facebook/css-layout,facebook/yoga,facebook/yoga,facebook/yoga,facebook/css-layout,facebook/css-layout,facebook/yoga,facebook/yoga,facebook/css-layout,facebook/css-layout,facebook/css-layout,facebook/yoga,facebook/yoga,facebook/yoga,facebook/css-layout,facebook/css-layout,facebook/css-layout