Removing a CollisionShape or CollisionPolygon from a sleeping RigidBody at runtime breaks gravity in Bullet physics

[hoontee]

Godot version:
3.2.3.rc1

OS/device including version:
Windows 10 2004

Issue description:
When removing a CollisionShape or CollisionPolygon from a sleeping RigidBody at runtime with the Bullet physics engine, its gravity stops working.
Does not occur with GodotPhysics.

Steps to reproduce:
Create a RigidBody with a CollisionShape, set sleeping to true, then attach the following script:

extends RigidBody

func _ready():
	var collision_shape = $CollisionShape
	add_child(collision_shape.duplicate())
	collision_shape.queue_free()

In this case, queue_free frees the old CollisionShape after Bullet initializes the physics body. It can be mitigated by calling free instead of queue_free.

Minimal reproduction project:
Physics.zip

[hoontee]

Not reproducible in 3.2.3.rc3. (Fixed by reverting #40185?)

[madmiraal]

Reopening, because I can reproduce this issue in both master (bc813fd) and 3.2.3.rc3 by delaying the replacement of the CollisionShape by one physics frame.

MRP 4.0: 40739-4.0.zip
MRP 3.2: 40739-3.2.zip