Debugger: Use handleInferiorPrepared also for AttachToRemoteProcess

Same pattern as the other scenarios.

Change-Id: I065783b9ced3ad31a1918b48b44116071bb98d75
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/debugger/gdb/gdbengine.cpp

@@ -4058,8 +4058,7 @@ void GdbEngine::setupInferior()
 
     if (rp.startMode == AttachToRemoteProcess) {
 
-        notifyEngineSetupOk();
-        runEngine();
+        handleInferiorPrepared();
 
     } else if (isAttachEngine()) {
         // Task 254674 does not want to remove them