Benchmarks should run with a configured memory limit

### Is your feature request related to a problem or challenge?

This would exercise the memory accounting feature, it would trigger operators to spill etc.
See this comment where the peak memory for running a query is 10GiB but some operators spill even with a memory limit of 50 GiB: https://github.com/apache/datafusion/issues/22526#issuecomment-4568611822

### Describe the solution you'd like
Instead of no memory limit, benchmarks should run with a default memory limit.

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

No specific file or test is named. Start by locating the benchmark entry point and the existing memory-accounting configuration, then determine how benchmarks currently run without a limit. Done means benchmarks use a default memory limit and exercise accounting behavior such as operator spilling.

Written by the indexing model from the issue text.