[CI][Bench] Refactor bench workflow

[lukaszstolarczuk]

No description provided.

[sarnex]

Any way we could move all of this environment setup into the file called by this workflow that runs the benchmark?

[lukaszstolarczuk]

hmm TBH I'm not sure if setting up env vars via script file would work in GHA in subsequent steps...?

Also, this script would be used only in this action, not sure if this would give any benefit...? For me it's good enough it's all now in one step, rather then scattered over a few steps.

[lukaszstolarczuk]

dispatch run: https://github.com/intel/llvm/actions/runs/19759131571/job/56617416122#step:19:1007
and results saved into dashboard: https://intel.github.io/llvm/benchmarks/?runs=test_refactor_BMG_L0v2