[VL] Spark 4.1: Diagnose and enable TODO SQL query test files

## Backend
VL (Velox)

## Bug description

11 SQL query test files are commented out as TODO in spark41 `VeloxSQLQueryTestSettings`. Each file needs to be diagnosed and either fixed directly or triaged to an existing issue by root cause.

This is a diagnostic/triage issue. Files will be routed to their root cause issues after diagnosis.

Spark 4.1 only.

Parent issue: #11550

### TODO files

| .sql file | spark40 | spark41 | Likely root cause |
|-----------|:-------:|:-------:|-------------------|
| cast.sql | 🟢 | TODO | TimeType or ANSI |
| describe.sql | 🟢 | TODO | Schema changes |
| literals.sql | 🟢 | TODO | TimeType |
| nonansi/cast.sql | 🟢 | TODO | ANSI differences (→ #10134) |
| nonansi/literals.sql | 🟢 | TODO | TimeType |
| subquery/.../exists-orderby-limit.sql | 🟢 | TODO | Plan changes |
| nonansi/st-functions.sql | N/A | TODO | Needs diagnosis |
| scripting/randomly_generated_scripts.sql | N/A | TODO | Needs diagnosis |
| st-functions.sql | N/A | TODO | Needs diagnosis |
| type-coercion-edge-cases.sql | N/A | TODO | Needs diagnosis |
| variant-field-extractions.sql | N/A | TODO | Variant (→ #11371) |

### Completion criteria

This issue can be closed when all 11 .sql files are either:
- Directly fixed and enabled, or
- Triaged to an existing issue (e.g., TimeType, Variant → #11371, ANSI → #10134) with a comment explaining the assignment.

Start with the Spark 4.1 VeloxSQLQueryTestSettings entries and the 11 listed TODO SQL files, comparing their Spark 4.0 status where available. Diagnose each file, then either fix and enable it or assign it to an existing root-cause issue with a comment. Done means all 11 files are enabled or explicitly triaged, including the referenced TimeType, ANSI, and Variant cases.

Written by the indexing model from the issue text.