ci: use codspeed simulation mode

[Boshen]

Replaces CodSpeed instrumentation mode with simulation mode.

[codspeed-hq]

Merging this PR will not alter performance

✅ 16 untouched benchmarks
⏩ 7 skipped benchmarks¹

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_{Comparing ci/codspeed-simulation-mode (23a358d) with main (a3fca29)²}

Footnotes

1. 7 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on main (9efb83b) during the generation of this report, so a3fca29 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩