Change the textalign setter to support RTL

Summary: @public Change the textalign setter to support RTL. In order to support text alignment according to layout style, move the textalign setter bridge function from ReactTextViewManager.java to ReactTextShadowNode.java and calculate it correctly on RCTTextUpdate.

Reviewed By: dmmiller

Differential Revision: D3597494

ReactAndroid/src/main/java/com/facebook/react/flat/RCTTextInput.java

@@ -125,7 +125,7 @@ public class RCTTextInput extends RCTVirtualText implements AndroidView, CSSNode
     super.onCollectExtraUpdates(uiViewOperationQueue);
     if (mJsEventCount != UNSET) {
       ReactTextUpdate reactTextUpdate =
-          new ReactTextUpdate(getText(), mJsEventCount, false, getPadding(), Float.NaN);
+          new ReactTextUpdate(getText(), mJsEventCount, false, getPadding(), Float.NaN, UNSET);
       // TODO: the Float.NaN should be replaced with the real line height see D3592781
       uiViewOperationQueue.enqueueUpdateExtraData(getReactTag(), reactTextUpdate);
     }