[no ticket] Enable parallel simulators for smoke tests

[clarmso]

📜 Tickets

Jira ticket
Github issue

💡 Description

This PR is to attempt the following to shorten the time spent on the Bitrise workflow for new PRs:

• Use two parallel simulators in smoke tests
• Use headless simulators for smoke tests and unit tests
• Remove BrowsingPDFTests from smoke tests for iOS 26

Some developers wonder why it takes 23-30 minutes to finish the tests for a PR. I may bring down the time to 21 minutes from start to finish.

🎥 Demos

Before	After

Demo

📝 Checklist

• I filled in the ticket numbers and a description of my work
• I updated the PR name to follow our PR naming guidelines
• I ensured unit tests pass and wrote tests for new code
• If working on UI, I checked and implemented accessibility (Dynamic Text and VoiceOver)
• If adding telemetry, I read the data stewardship requirements and will request a data review
• If adding or modifying strings, I read the guidelines and will request a string review from l10n
• If needed, I updated documentation and added comments to complex code

[mobiletest-ci-bot]

🧹 Tidy commit

Just 1 file(s) touched. Thanks for keeping it clean and review-friendly!

💬 Description craftsman

Great PR description! Reviewers salute you 🫡

✅ Per-file coverage

All changed files meet the threshold of 35.0%.

Generated by 🚫 Danger Swift against f738a3f

[github-actions]

🚀 PR merged to main, targeting version: 144.2