Fixup Yoga UT compilation on non-clang compilers (#1333)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1333

Yoga is compiled on more than clang, both internally, and in OSS. D47345669 added unguarded usage of `
#pragma clang diagnostic push` to Yoga UTs which will cause unrecognized pragma errors if building the tests on other platforms.

The code here is flagged for implicitly converting enum to float. This is test code which is using the enum as an arbitrary differentiating input, so I just changed this to an explicit cast, which I assume should silence the warning.

Reviewed By: NuriAmari

Differential Revision: D47460301

fbshipit-source-id: 952ff61e0c26deb8bbff8b860faf30896753a3bd

tests/YGNodeCallbackTest.cpp

@@ -33,11 +33,7 @@ TEST(YGNode, measure_with_measure_fn) {
 
   n.setMeasureFunc(
       [](YGNode*, float w, YGMeasureMode wm, float h, YGMeasureMode hm) {
-// TODO: Correctly fix enum - float conversion warning: T158155910
+        return YGSize{w * static_cast<int>(wm), h / static_cast<int>(hm)};
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wenum-float-conversion"
-        return YGSize{w * wm, h / hm};
-#pragma clang diagnostic pop
       });
 
   ASSERT_EQ(
@@ -62,19 +58,11 @@ TEST(YGNode, switching_measure_fn_types) {
   auto n = YGNode{};
   n.setMeasureFunc(
       [](YGNode*, float, YGMeasureMode, float, YGMeasureMode, void*) {
-// TODO: Properly fix enum - float conversion warning: T158155910
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wenum-float-conversion"
         return YGSize{};
-#pragma clang diagnostic pop
       });
   n.setMeasureFunc(
       [](YGNode*, float w, YGMeasureMode wm, float h, YGMeasureMode hm) {
-// TODO: Properly fix enum - float conversion warning: T158155910
+        return YGSize{w * static_cast<int>(wm), h / static_cast<int>(hm)};
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wenum-float-conversion"
-        return YGSize{w * wm, h / hm};
-#pragma clang diagnostic pop
       });
 
   ASSERT_EQ(