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/Module.h

@@ -59,7 +59,7 @@ class Module
     : public RefCounted<Module>
     , public Weakable<Module> {
 public:
-    virtual ~Module();
+    virtual ~Module() = default;
 
     Realm& realm() { return *m_realm.cell(); }
     Realm const& realm() const { return *m_realm.cell(); }