Support variable query repetition counts

[caetanosauer]

Summary

• Allow benchmark result rows to contain any consistent number of repetitions greater than or equal to three.
• Keep the first repetition as the cold measurement and use all remaining repetitions when calculating the hot measurement.
• Update result parsing, validation, documentation, and the shared runner without changing the default of three repetitions.
• Add 10-repetition results for Salesforce Hyper on c7a.metal-48xl for native storage, a single Parquet file, and partitioned Parquet files.

Validation

• python3 validate-results.py: validated 33,014 result files (982 active), with no errors.
• Regenerated data.generated.js and checked its JavaScript syntax with node --check.
• git diff --check passes.