[Refractor] copy-pasted codes in the "driver.py"

[Shaoting-Feng]

Describe the problem

There are multiple copy-pasted codes in the "driver.py". We need to refactor it. Some example:

• execute_one_request and execute_one_request_with_output
• execute_all and execute_all_with_output
• execute_openai_request and execute_openai_request_with_output
• run_experiment and run_multi_turn_experiment

In these similar functions, the difference may only be one additional return value, so it is a good idea to delete the copy-pasted codes and just use one function in the above pairs.

How to test

For the first functions in these pairs, you can use test_lmcache_local_cpu to test. For the second functions in these pairs, you can use test_multi_turn to test.