GdbDebugger: add fast restart for debugging

Change-Id: Ie51847de912748d05a6b208bec82fd612d777202
Reviewed-by: hjk <hjk121@nokiamail.com>
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>

src/plugins/debugger/debuggerengine.h

@@ -334,6 +334,7 @@ protected:
     virtual void runEngine() = 0;
     virtual void shutdownInferior() = 0;
     virtual void shutdownEngine() = 0;
+    virtual void resetInferior() {}
 
     virtual void detachDebugger();
     virtual void exitDebugger();