Make mutation sorting more clear

Summary:
This is more insurance against future changes than fixing any existing bugs. In a very small number of cases it looks like this sorting isn't working, for reasons that are not easily reproducible (way less than 1 in 10000 times for me, if that) and not obvious, since we're sorting vectors in a canonical and straightforward way.

Again, this insures that logic won't change in the future.

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D27492936

fbshipit-source-id: 7f47e44ac1101915e1a0433c8f0a50a3c6a0c7b3

ReactCommon/react/renderer/animations/LayoutAnimationKeyFrameManager.h

@@ -331,9 +331,12 @@ static inline bool shouldFirstComeBeforeSecondMutation(
     // Make sure that removes on the same level are sorted - highest indices
     // must come first.
     if (lhs.type == ShadowViewMutation::Type::Remove &&
-        lhs.parentShadowView.tag == rhs.parentShadowView.tag &&
-        lhs.index > rhs.index) {
-      return true;
+        lhs.parentShadowView.tag == rhs.parentShadowView.tag) {
+      if (lhs.index > rhs.index) {
+        return true;
+      } else {
+        return false;
+      }
     }
   }