"MSL conversion error: Aliasing arrayed discrete descriptors is currently not supported."

Consider this a vote to get this support going. Thanks for all you guys have done on this amazing project btw.

```glsl

layout(set = 3, binding = 0) readonly buffer TrimParams
{
int numTrims;
} trimParams;

layout(set = 3, binding = 0) readonly buffer TrimLoop
{
int numPositions;
bool inner;
vec2 pos[];
} trim[];
```

Start by reproducing the MSL conversion error with the GLSL snippet in the issue, focusing on the aliased arrayed discrete descriptors. Determine the conversion behavior needed for the two TrimParams and TrimLoop declarations; done means this input converts without the reported unsupported-aliasing error.

Written by the indexing model from the issue text.