Fix flex within max width constraint

Summary:
Max dimension constraints were not correctly passed down to children.

see https://github.com/facebook/css-layout/issues/230 for more info
fixes #230

Reviewed By: gkassabli

Differential Revision: D4147199

fbshipit-source-id: feb335eb8687a1b7939ee8cd8649e455e0c069a9

gentest/fixtures/CSSLayoutMinMaxDimensionTest.html

@@ -29,3 +29,9 @@
   <div style="width: 50px; height: 50px;"></div>
   <div style="width: 50px; height: 50px;"></div>
 </div>
+
+<div id="flex_grow_within_max_width" style="width: 200px; height: 100px;">
+  <div style="flex-direction: row; max-width: 100px;">
+    <div style="height: 20px; flex-grow: 1;"></div>
+  </div>
+</div>