Add support for aspectRatio style prop

Summary:
Expose aspectRatio style prop from css-layout to React Native.

This means the following will now work:

    <View style={{backgroundColor: 'blue', aspectRatio: 1}}/>

Reviewed By: javache

Differential Revision: D4226472

fbshipit-source-id: c8709a7c0abbf77089a4e867879b42dcd9116f65

ReactAndroid/src/main/java/com/facebook/react/uimanager/ReactShadowNode.java

@@ -576,6 +576,10 @@ public class ReactShadowNode {
     mCSSNode.setFlexBasis(flexBasis);
   }
 
+  public void setStyleAspectRatio(float aspectRatio) {
+    mCSSNode.setStyleAspectRatio(aspectRatio);
+  }
+
   public void setFlexDirection(CSSFlexDirection flexDirection) {
     mCSSNode.setFlexDirection(flexDirection);
   }