Memory held on in `datafusion-cli` (reported memory size increases over time)

### Describe the bug

When running several memory consuming queries in datafusion-cli, the system memory won't be released after the query ends, the memory usage from different queries are accumulated, until `datafusion-cli` is exited.

### To Reproduce

1. Compile and run datafusion-cli (commit 8c42a65a4)
2. I'm using MacOS's `Application Monitor` GUI to check memory usage of `datafusion-cli` process
3. Execute several memory-intensive queries, and memory usage accumulates over time.
```
select *
from generate_series(1,100000000) as t1(v1)
order by v1;

-- datafusion-cli process: 1.5G memory

select *
from generate_series(1,200000000) as t1(v1)
order by v1;

-- datafusion-cli process: 3.2G memory

select 1;

-- Still 3.2G
```

### Expected behavior

_No response_

### Additional context

_No response_

Compile and run datafusion-cli at commit 8c42a65a4, then reproduce the two memory-intensive generate_series queries followed by SELECT 1 while monitoring the process in macOS Application Monitor. Trace the datafusion-cli query lifecycle to determine why memory remains allocated after each query; done means repeated queries no longer cause memory usage to accumulate after completion.

Written by the indexing model from the issue text.