inspector: add missing virtual destructor

This fixes a resource leak detected by a Coverity scan.

PR-URL: #13198
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Aleksei Koziatinskii <ak239spb@gmail.com>

src/inspector_agent.cc

@@ -195,7 +195,7 @@ class JsBindingsSessionDelegate : public InspectorSessionDelegate {
                      v8::WeakCallbackType::kParameter);
   }
 
-  virtual ~JsBindingsSessionDelegate() {
+  ~JsBindingsSessionDelegate() override {
     session_.Reset();
     receiver_.Reset();
     callback_.Reset();

src/inspector_agent.h

@@ -37,6 +37,7 @@ namespace inspector {
 
 class InspectorSessionDelegate {
  public:
+  virtual ~InspectorSessionDelegate() = default;
   virtual bool WaitForFrontendMessage() = 0;
   virtual void OnMessage(const v8_inspector::StringView& message) = 0;
 };