[V1] fix torch profiling for V1 offline scenarios

[divakar-amd]

Currently, the torch profiler doesn't capture anything useful for V1 offline benchmarking scenarios as the gpu_worker is attached to a different process.  This PR:

1. Refactors offline benchmarking scripts to capture profiler information for both V0 & V1 mode.
2. Dumps kernels summary table automatically when the profiler is stopped.

• The PR replaces --profile-result-dir and checks if the VLLM_TORCH_PROFILER_DIR environment variable is set before enabling profiling

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[youkaichao]

LGTM, thanks for the fix!

[DarkLight1337]

Can you merge from main to fix CI?

[divakar-amd]

Can you merge from main to fix CI?

@DarkLight1337 Hi, anything else required here?

[DarkLight1337]

Docker build previously failed, retrying now

[ProExpertProg]

Why remove the default profile dir? IMO the default worked fine, and we should restore it so VLLM_TORCH_PROFILER_DIR doesn't need to be specified manually every time