Benchmarks for perf

[ollz272]

Change Summary

Just a quick follow up to the feature to give some benchmarks to test performance. I saw about a 3% improvement locally when building with these

Related issue number

Checklist

• Unit tests for the changes exist
• Documentation reflects the changes where applicable
• Pydantic tests pass with this pydantic-core (except for expected changes)
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[codspeed-hq]

CodSpeed Performance Report

Merging #1756 will not alter performance

_{Comparing ollz272:benchmarks-for-perf (090cd08) with main (04b296b)}

Summary

✅ 157 untouched benchmarks
🆕 2 new benchmarks

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
🆕	test_datetime_milliseconds	N/A	25.3 µs	N/A
🆕	test_datetime_seconds	N/A	25.1 µs	N/A

[davidhewitt]

Just needs the groups adjusting, otherwise lgtm, thanks!

[davidhewitt]

Thanks