Fix sizing of non strech items

Summary:
Fixes the sizing of items so that under most scenarios it calcultes its height by it's content for non exact measurings. This introduces a new useLegacyStretchBehaviour flag on the config to opt out of this change as it is breaking.

See facebook/yoga#505
Closes https://github.com/facebook/yoga/pull/506

Reviewed By: astreet

Differential Revision: D4954016

Pulled By: emilsjolander

fbshipit-source-id: d28bd5d174cd76951fb94df85e3b0cfab7f81ff7

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

@@ -87,6 +87,7 @@ public class ReactShadowNode {
       if (sYogaConfig == null) {
         sYogaConfig = new YogaConfig();
         sYogaConfig.setPointScaleFactor(0f);
+        sYogaConfig.setUseLegacyStretchBehaviour(true);
       }
       if (node == null) {
         node = new YogaNode(sYogaConfig);