[1.7 BLOCKING LIVE] Corpses of entities without gravity float up.

Verification Builds: 1117901

Summary: When an entity that has the `has_gravity: false` option in the physics component is killed, the corpse will float upwards before disappearing as usual.

Impact: This makes the instruction reader in Logic0 look extremely odd whenever it is killed, which happens regularly.

Repro Steps:

1. Download Logic0, open it and press the green button behind you.
2. Flick the green lever.

Observed Results: Once the small robot falls off of the green blocks it is killed and its corpse floats up into the air.

Expected Results: The corpse of the small robot stays on the ground where it was teleported before killing it.

Screenshots / Videos Attached: No.

Note: This could possibly be related to the new knockback change for corpses (53151 / MCPE-19222).

Regression Build: 1.6.0.8