Minor: Log TPCH benchmark results

[alamb]

Which issue does this PR close?

N/A

Rationale for this change

I wanted to validate y POC grouping code that it got the right answer when running benchmarks

What changes are included in this PR?

the tpch benchmark driver now shows the output if RUST_LOG is enabled

Before this PR

cargo run --profile dev --bin tpch -- benchmark datafusion --iterations 5 --format parquet -q 17 --path <data> 
...

Running benchmarks with the following options: DataFusionBenchmarkOpt { query: Some(17), debug: false, iterations: 5, partitions: 2, batch_size: 8192, path: "/Users/alamb/Software/arrow-datafusion/benchmarks/data/", file_format: "parquet", mem_table: false, output_path: None, disable_statistics: false }
Query 17 iteration 0 took 6383.7 ms and returned 1 rows
Query 17 iteration 1 took 6341.2 ms and returned 1 rows
Query 17 iteration 2 took 6337.4 ms and returned 1 rows
Query 17 iteration 3 took 6202.9 ms and returned 1 rows
Query 17 iteration 4 took 6222.3 ms and returned 1 rows
Query 17 avg time: 6297.51 ms

After this PR:

 cargo run --profile dev --bin tpch -- benchmark datafusion --iterations 5 --format parquet -q 17 --path <data> 
...
Running benchmarks with the following options: DataFusionBenchmarkOpt { query: Some(17), debug: false, iterations: 5, partitions: 2, batch_size: 8192, path: "/Users/alamb/Software/arrow-datafusion/benchmarks/data/", file_format: "parquet", mem_table: false, output_path: None, disable_statistics: false }
[2023-06-30T15:33:26Z INFO  tpch] output:

    +-------------------+
    | avg_yearly        |
    +-------------------+
    | 348406.0542857143 |
    +-------------------+


Query 17 iteration 0 took 6401.7 ms and returned 1 rows
[2023-06-30T15:33:33Z INFO  tpch] output:

    +-------------------+
    | avg_yearly        |
    +-------------------+
    | 348406.0542857143 |
    +-------------------+


Query 17 iteration 1 took 6348.3 ms and returned 1 rows
...

Are these changes tested?

No -- they are a debugging tool

Are there any user-facing changes?

No -- internal debugging tool