Measure nodes which have margin: auto and align-item: stretch

Summary:
If you have a measurable node and set ```marign-left: auto``` + ```align-item:stretch``` on it, it won't get measured and they get a width/height of ```-(nan)```. This change fixes that behaviour. Fixes #644.
Closes facebook/yoga#645

Differential Revision: D6413512

Pulled By: emilsjolander

fbshipit-source-id: 755febeb33bb0d4520ca6b3c28d56ac333e4a14d

ReactCommon/yoga/yoga/Yoga.cpp

@@ -2327,7 +2327,9 @@ static void YGNodelayoutImpl(const YGNodeRef node,
                                             availableInnerCrossDim) &&
                    measureModeCrossDim == YGMeasureModeExactly &&
                    !(isNodeFlexWrap && flexBasisOverflows) &&
-                   YGNodeAlignItem(node, currentRelativeChild) == YGAlignStretch) {
+                   YGNodeAlignItem(node, currentRelativeChild) == YGAlignStretch &&
+                   YGMarginLeadingValue(currentRelativeChild, crossAxis)->unit != YGUnitAuto &&
+                   YGMarginTrailingValue(currentRelativeChild, crossAxis)->unit != YGUnitAuto) {
           childCrossSize = availableInnerCrossDim;
           childCrossMeasureMode = YGMeasureModeExactly;
         } else if (!YGNodeIsStyleDimDefined(currentRelativeChild,
@@ -2363,7 +2365,9 @@ static void YGNodelayoutImpl(const YGNodeRef node,
 
         const bool requiresStretchLayout =
             !YGNodeIsStyleDimDefined(currentRelativeChild, crossAxis, availableInnerCrossDim) &&
-            YGNodeAlignItem(node, currentRelativeChild) == YGAlignStretch;
+            YGNodeAlignItem(node, currentRelativeChild) == YGAlignStretch &&
+            YGMarginLeadingValue(currentRelativeChild, crossAxis)->unit != YGUnitAuto &&
+            YGMarginTrailingValue(currentRelativeChild, crossAxis)->unit != YGUnitAuto;
 
         const float childWidth = isMainAxisRow ? childMainSize : childCrossSize;
         const float childHeight = !isMainAxisRow ? childMainSize : childCrossSize;