Object sinks after move

[BenjaminDeleze]

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Describe the Bug After some actions, such as moving an object, the object sinks into the ground during a step. This is most likely because the contact points are not calculated correctly. A part of the problem have been fixed in #4070. However, several other situations remain wrong:

• Supervisor saveState then loadState: bugs even if the node did not move between the save and the load.
• Supervisor saveState then loadState + node.resetPhysics: **works since #4070 **, but we do not want to use node.resetPhysics with loadState
• Move/Insert node in SceneTree
• Move node in GUI
• Reset: bugs (even if nothing moved) only in multi threading

Regarding the reset (only in multithreading), it is disturbing because you can have a bug by doing something like thing:

• Load a world with a ball on a floor
• Step: nothing move
• Reset
• Step: the ball sinks on the ground.

I thought that handleInitialCollisions (called at the loading of the world) was the solution, but it is also called in the reset and does not work.