LayoutData - added explicit default fields values initialization (#1802)

Summary:
X-link: https://github.com/facebook/react-native/pull/50227

Explicit defaults add 'strictness' and take the guesswork out of what's going on in places like this:

6455a848a7/yoga/algorithm/CalculateLayout.cpp (L2345)

Changelog: [Internal]

Pull Request resolved: https://github.com/facebook/yoga/pull/1802

Reviewed By: javache

Differential Revision: D71687310

Pulled By: NickGerleman

fbshipit-source-id: f11d18aa68ce7ccd17fb1d5af0e729e8c0711cf9

yoga/event/event.h

@@ -36,12 +36,12 @@ enum struct LayoutPassReason : int {
 };
 
 struct LayoutData {
-  int layouts;
-  int measures;
-  uint32_t maxMeasureCache;
-  int cachedLayouts;
-  int cachedMeasures;
-  int measureCallbacks;
+  int layouts = 0;
+  int measures = 0;
+  uint32_t maxMeasureCache = 0;
+  int cachedLayouts = 0;
+  int cachedMeasures = 0;
+  int measureCallbacks = 0;
   std::array<int, static_cast<uint8_t>(LayoutPassReason::COUNT)>
       measureCallbackReasonsCount;
 };