Developer Guilherme Rambo on his Twitter account shared a video that shows how the iPhone 8 will call the list of running applications without the physical button "Home". The video was found in one of the beta versions of iOS 11.
Switching between applications occurs using the gesture that is currently used to call the Control Center. Presumably, this option to call the multitask menu will be present only in the firmware for the iPhone 8.
Guilherme says that although he discovered this video only now, he is present in beta versions of iOS 11 since May. This may not be the final decision, but only one of the gesture options that Apple implements for the iPhone 8.
Also, the developer published a video that shows how the svayp on the right of the lock screen calls up the Control Center instead of the camera. This solution seems extremely doubtful, because to call the desired menu requires an additional gesture.