[SPARK-54668] [SQL] [TEST-ONLY] Add tests for CTEs in multi-children operators

### What changes were proposed in this pull request?
We miss some golden files for CTEs in multi-children operators. In this issue I propose to add it.

### Why are the changes needed?
To improve the coverage for the explained case.

### Does this PR introduce _any_ user-facing change?
No.

### How was this patch tested?
Testing change.

### Was this patch authored or co-authored using generative AI tooling?
No.

Closes #53442 from mihailoale-db/addtestsctesmultichildren.

Authored-by: mihailoale-db <[email protected]>
Signed-off-by: Daniel Tenedorio <[email protected]>

Author: mihailoale-db