Libraries: Use default constructors/destructors in LibJS

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#cother-other-default-operation-rules

"The compiler is more likely to get the default semantics right and
you cannot implement these functions better than the compiler."

Userland/Libraries/LibJS/Runtime/Object.h

@@ -49,7 +49,7 @@ public:
     explicit Object(Object& prototype);
     explicit Object(Shape&);
     virtual void initialize(GlobalObject&) override;
-    virtual ~Object();
+    virtual ~Object() = default;
 
     enum class PropertyKind {
         Key,