Some aggregation spilling unit tests don't cover spilling to disk logic

### Describe the bug

When I debug the failed tests in #11943 , I finally found that such tests not conver the `spilling to disk logic` in `main` branch actually(if convered, they may fail as #11943...)

And in #11943, the memory usage in test are changed, and trigger the `spilling to disk`, and lead to test failures.

### To Reproduce

- add a `panic` at the beginning of `update_merged_stream` function in `row_hash.rs`.
- run `aggregate_grouping_sets_source_not_yielding_with_spill` and `aggregate_grouping_sets_with_yielding_with_spill` tests.
- you will found them passed.

### Expected behavior

They should go the disk spilling path and pass.

### Additional context

_No response_

Start with row_hash.rs and the update_merged_stream function, then run aggregate_grouping_sets_source_not_yielding_with_spill and aggregate_grouping_sets_with_yielding_with_spill. Verify that the tests actually exercise the disk-spilling path rather than passing without entering it, and that they still pass when that path is used.

Written by the indexing model from the issue text.