Migrate YogaNodeJNIBase.java to Kotlin

Summary:
Migrate YogaNodeJNIBase.java to YogaNodeJNIBase.kt, the last hand-written Java source file in the Yoga core library. This required converting all function overrides to Kotlin property overrides where the abstract YogaNode class declares them as val/var properties. Also changed nativePointer visibility in YogaConfigJNIBase from protected to internal to maintain same-module access that Java protected provided via package access.

Changelog:
[Internal] -

Differential Revision: D104666335

Author: cortinico

java/com/facebook/yoga/YogaNode.kt

@@ -226,9 +226,9 @@ public abstract class YogaNode : YogaProps {
 
   public abstract val layoutDirection: YogaDirection
 
-  abstract override fun setMeasureFunction(measureFunction: YogaMeasureFunction)
+  abstract override fun setMeasureFunction(measureFunction: YogaMeasureFunction?)
 
-  abstract override fun setBaselineFunction(yogaBaselineFunction: YogaBaselineFunction)
+  abstract override fun setBaselineFunction(yogaBaselineFunction: YogaBaselineFunction?)
 
   public abstract val isMeasureDefined: Boolean