Revert of [Fix dimension check for STRETCH children]

Summary: We had a layout issue in Ads Manager after updating to the latest version of css-layout on react-native. I bisected the change to facebook/yoga@909c141. It changes the condition and breaks the behavior that we had. This change was not covered by a unit test so I added one.

Closes facebook/yoga#131

Reviewed By: @​svcscm

Differential Revision: D2476924

Pulled By: @vjeux

React/Layout/Layout.c

@@ -1004,7 +1004,7 @@ static void layoutNodeImpl(css_node_t *node, float parentMaxWidth, css_direction
           if (alignItem == CSS_ALIGN_STRETCH) {
             // You can only stretch if the dimension has not already been set
             // previously.
-            if (isUndefined(child->layout.dimensions[dim[crossAxis]])) {
+            if (!isDimDefined(child, crossAxis)) {
               child->layout.dimensions[dim[crossAxis]] = fmaxf(
                 boundAxis(child, crossAxis, containerCrossAxis -
                   paddingAndBorderAxisCross - getMarginAxis(child, crossAxis)),