[Request]: CI: Pre-pull most-used images for CI tests.

### Feature or enhancement request details

A potentially significant performance bottleneck for CI runs is image pull. The containerization ImageStore does not deduplicate concurrent requests for the same image, and while such a workload would be very uncommon in real life, it is what happens on a CI integration test run.

Pre-pulling a few of the most used images should improve integration test runtimes. We don't need to pull all images, and probably don't want to because preserving some nondeterminism/chaos by having multiple real image fetches running at once is a good stress test.

### Code of Conduct

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