core/debugger: Implement new GDB stub debugger

src/yuzu/bootmanager.h

@@ -54,15 +54,6 @@ public:
      */
     void run() override;
 
-    /**
-     * Steps the emulation thread by a single CPU instruction (if the CPU is not already running)
-     * @note This function is thread-safe
-     */
-    void ExecStep() {
-        exec_step = true;
-        running_cv.notify_all();
-    }
-
     /**
      * Sets whether the emulation thread is running or not
      * @param running Boolean value, set the emulation thread to running if true
@@ -99,7 +90,6 @@ public:
     }
 
 private:
-    bool exec_step = false;
     bool running = false;
     std::stop_source stop_source;
     std::mutex running_mutex;