3.6 Bool type uniform in vertex function of shader makes mesh look weird (AMD latest driver)

### Tested versions

- Reproducible in: 3.6.2.stable
- Not Reproducible in: 4.6.stable

### System information

Windows 11 - Godot v3.6.2.stable - AMD Radeon 780M

### Issue description

I'm sorry I can't summarize it properly in the title.
My graphic card is 780M, latest driver (26.1.1)
If a MeshInstance transform != Transform(), it will looks like this.

### Steps to reproduce

Add a MeshInstance node, set a SphereMesh.
Add a shader material (or just convert from spatial material).
In shader code, write something like this:
```
shader_type spatial;

uniform bool test_bool;
void vertex() {
if (test_bool) {}
}
```
Change the posistion(or rotation or scale) of the MeshInstance.

### Minimal reproduction project (MRP)

[bug-report.zip](https://github.com/user-attachments/files/25294823/bug-report.zip)