Overkill doesn't gib zombie corpse

### Describe the bug

It happened in the recent experimental version and the lastest. I found out that almost all the humanoid enemies corpses didn't become pulped after I dealt damage that is twice their base HP.

### Steps to reproduce

1. Debug my character to have really high strength that deal huge damage (250~300) using high bashing damage weapon Heavy sledge hammer on common zombies.
2. The second time I created a reasonable stats character with 14 str only and leave the rest 8. I started with High Tech Low Life scenario and installed myself hydraulic muscle bionic and equiped myself a heavy sledge hammer. Still not work though, again, non-humanoid enemies don't have this issue.

### Expected behavior

Some humanoid enemies, or at least normal zombies, should be pulped and explode into gory messes after receiving overkill damage.

### Screenshots

_No response_

### Versions and configuration

- OS: Android 9
- Version: Experiment bb34fdb
- Mods: None.

### Additional context

_No response_

No source files, tests, or entry points are named. Start by reproducing the overkill attack against a normal humanoid zombie, then trace the damage and corpse-pulping behavior for humanoid and non-humanoid enemies. Done means humanoid corpses, including normal zombies, are pulped after receiving more than twice their base HP in damage.

Written by the indexing model from the issue text.