llama-bench: rename DB table name from test to llama_bench

[yeahdongcn]

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This PR is a follow-up based on comments from @JohannesGaessler :

I think it would be better to have a more specific name. (The table for llama-bench is just named "test", that could also be improved upon.)

Testing Done

root@ff759de5dd90:/ws# ./scripts/compare-commits.sh e1c2f3ea0 737f78c34 llama-bench -m /models/DeepSeek-R1-Distill-Qwen-7B-Q4_K_M.gguf
 -ngl 999
+ commit1=e1c2f3ea0
+ commit2=737f78c34
+ tool=llama-bench
+ additional_args='-m /models/DeepSeek-R1-Distill-Qwen-7B-Q4_K_M.gguf -ngl 999'
+ '[' llama-bench '!=' llama-bench ']'
+ ./scripts/compare-llama-bench.py --check
+ '[' llama-bench = llama-bench ']'
+ db_file=llama-bench.sqlite
+ target=llama-bench
+ run_args='-o sql -oe md -m /models/DeepSeek-R1-Distill-Qwen-7B-Q4_K_M.gguf -ngl 999'
+ rm -f llama-bench.sqlite
+ '[' -n '' ']'
+ dir=build-bench
+ git checkout e1c2f3ea0
Previous HEAD position was 737f78c34 llama-bench: rename DB table name from test to llama_bench
HEAD is now at e1c2f3ea0 1
+ run
+ rm -fr build-bench
+ cmake -B build-bench -S .
++ nproc
+ cmake --build build-bench -t llama-bench -j 12
+ build-bench/bin/llama-bench -o sql -oe md -m /models/DeepSeek-R1-Distill-Qwen-7B-Q4_K_M.gguf -ngl 999
+ sqlite3 llama-bench.sqlite
| model                          |       size |     params | backend    | threads |            test |                  t/s |
| ------------------------------ | ---------: | ---------: | ---------- | ------: | --------------: | -------------------: |
| qwen2 7B Q4_K - Medium         |   4.36 GiB |     7.62 B | CPU        |       6 |           pp512 |         41.91 ± 1.66 |
| qwen2 7B Q4_K - Medium         |   4.36 GiB |     7.62 B | CPU        |       6 |           tg128 |         10.37 ± 0.20 |

build: e1c2f3ea0 (6055)
+ git checkout 737f78c34
Previous HEAD position was e1c2f3ea0 1
HEAD is now at 737f78c34 llama-bench: rename DB table name from test to llama_bench
+ run
+ rm -fr build-bench
+ cmake -B build-bench -S .
++ nproc
+ cmake --build build-bench -t llama-bench -j 12
+ build-bench/bin/llama-bench -o sql -oe md -m /models/DeepSeek-R1-Distill-Qwen-7B-Q4_K_M.gguf -ngl 999
+ sqlite3 llama-bench.sqlite
| model                          |       size |     params | backend    | threads |            test |                  t/s |
| ------------------------------ | ---------: | ---------: | ---------- | ------: | --------------: | -------------------: |
| qwen2 7B Q4_K - Medium         |   4.36 GiB |     7.62 B | CPU        |       6 |           pp512 |         41.45 ± 1.78 |
| qwen2 7B Q4_K - Medium         |   4.36 GiB |     7.62 B | CPU        |       6 |           tg128 |         10.29 ± 0.15 |

build: 737f78c34 (6054)
+ ./scripts/compare-llama-bench.py -b e1c2f3ea0 -c 737f78c34 --tool llama-bench -i llama-bench.sqlite
| CPU                                 | Model           | Test   |   t/s xd/llama_bench |   t/s 737f78c34 |   Speedup |
|:------------------------------------|:----------------|:-------|---------------------:|----------------:|----------:|
| 12th Gen Intel(R) Core(TM) i5-12400 | qwen2 7B Q4_K_M | pp512  |                41.91 |           41.45 |      0.99 |
| 12th Gen Intel(R) Core(TM) i5-12400 | qwen2 7B Q4_K_M | tg128  |                10.37 |           10.29 |      0.99 |
root@ff759de5dd90:/ws#