Debugger: Merge EngineSetup and InferiorSetup start phases

It was needed in the past to trigger e.g. gdbserver setup in
remote cases which is nowadays handled by separate RunWorkers.

Change-Id: I30bce071dab0779cce2e7abef7b31550d8539461
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/debugger/qml/qmlcppengine.h

@@ -105,7 +105,6 @@ protected:
     void doUpdateLocals(const UpdateParameters &up) override;
 
     void setupEngine() override;
-    void setupInferior() override;
     void runEngine() override;
     void shutdownInferior() override;
     void shutdownEngine() override;