Fix dynamic_cast (RTTI) by adding key function to ShadowNodeWrapper again (#45290)

Summary:
This PR restores the virtual destructor for `ShadowNodeWrapper` which was added in https://github.com/facebook/react-native/pull/33500 and unfortunately removed in https://github.com/facebook/react-native/pull/40864.

The virtual destructor here serves as a key function. Without a key function, `obj.hasNativeState<ShadowNodeWrapper>(rt)` **does not** work correctly between shared library boundaries on Android and always returns false.

We need this pretty badly in third-party libraries like react-native-reanimated or react-native-gesture-handler.

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[ANDROID] [FIXED] - Fix dynamic_cast (RTTI) for ShadowNodeWrapper when accessed by third-party libraries again

Pull Request resolved: https://github.com/facebook/react-native/pull/45290

Test Plan: This patch fixes an issue in Reanimated's fabric-example app.

Reviewed By: fabriziocucci

Differential Revision: D59375554

Pulled By: javache

fbshipit-source-id: 09f3eda89a67c26d6dacca3428e08d1b7138d350

packages/react-native/ReactCommon/react/renderer/core/ShadowNode.cpp

@@ -410,4 +410,10 @@ SharedDebugStringConvertibleList ShadowNode::getDebugProps() const {
 }
 #endif
 
+// Explicitly define destructors here, as they need to exist in order to act as
+// a "key function" for the ShadowNodeWrapper class -- this allows for RTTI to
+// work properly across dynamic library boundaries (i.e. dynamic_cast that is
+// used by getNativeState method)
+ShadowNodeWrapper::~ShadowNodeWrapper() = default;
+
 } // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/core/ShadowNode.h

@@ -282,6 +282,11 @@ struct ShadowNodeWrapper : public jsi::NativeState {
   explicit ShadowNodeWrapper(ShadowNode::Shared shadowNode)
       : shadowNode(std::move(shadowNode)) {}
 
+  // The below method needs to be implemented out-of-line in order for the class
+  // to have at least one "key function" (see
+  // https://itanium-cxx-abi.github.io/cxx-abi/abi.html#vague-vtable)
+  ~ShadowNodeWrapper() override;
+
   ShadowNode::Shared shadowNode;
 };