[crater] Print per-target runtime

[cmyr]

It's otherwise tricky to see what targets take the longest to run, which is something I'm curious about.

[gemini-code-assist]

Summary of Changes

Hello @cmyr, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the crater tool by introducing detailed logging and reporting of individual target execution times. The primary goal is to provide better visibility into which targets consume the most time, aiding in performance analysis and optimization efforts.

Highlights

• Improved Time Measurement and Reporting: A new utility function human_readable_duration has been introduced to format std::time::Duration into a human-readable string (e.g., "XhYmZ.ZZs").
• Per-Target Runtime Logging: The run_all function now records and logs the execution time for each individual target, making it easier to identify slow-running components.
• Centralized Duration Formatting: The previous custom time formatting logic has been replaced with the new human_readable_duration utility across various parts of the codebase, including CI and HTML reporting.

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[gemini-code-assist]

Code Review

This pull request adds per-target runtime printing, which is a great feature for identifying performance bottlenecks. The implementation introduces a reusable human_readable_duration function with tests, which is well done. My main feedback is a suggestion to refactor the time calculation logic within human_readable_duration to improve readability and maintainability by using the modulo operator.

[PauloRosarioData]

LGTM

[PauloRosarioData]

LGTM