DevTools: Use default constructors/destructors

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/DevTools/HackStudio/Debugger/DebuggerVariableJSObject.cpp

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2021, Matthew Olsson <matthewcolsson@gmail.com>
  * Copyright (c) 2021, Hunter Salyer <thefalsehonesty@gmail.com>
+ * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -25,10 +26,6 @@ DebuggerVariableJSObject::DebuggerVariableJSObject(const Debug::DebugInfo::Varia
 {
 }
 
-DebuggerVariableJSObject::~DebuggerVariableJSObject()
-{
-}
-
 JS::ThrowCompletionOr<bool> DebuggerVariableJSObject::internal_set(const JS::PropertyKey& property_key, JS::Value value, JS::Value)
 {
     auto& vm = this->vm();