Remove useless store in CSSLayout.c

Reviewed By: emilsjolander

Differential Revision: D4159938

fbshipit-source-id: 8b9ff3896c0e222e8e89546881129214bc6ba566

React/CSSLayout/CSSLayout.c

@@ -1939,12 +1939,10 @@ static void layoutNodeImpl(const CSSNodeRef node,
 
             if (!CSSValueIsUndefined(child->style.maxDimensions[CSSDimensionWidth])) {
               childWidth = child->style.maxDimensions[CSSDimensionWidth];
-              childWidthMeasureMode = CSSMeasureModeAtMost;
             }
 
             if (!CSSValueIsUndefined(child->style.maxDimensions[CSSDimensionHeight])) {
               childHeight = child->style.maxDimensions[CSSDimensionHeight];
-              childHeightMeasureMode = CSSMeasureModeAtMost;
             }
 
             // If the child defines a definite size for its cross axis, there's