Enable running iOS tests

[steveisok]

Now that we're hooked into CI, we need to enable running tests both locally and with helix.

• Add sample project for easy testing: [mono] Add iOS sample (AOT, arm64) #33633
• Generate .app per test suite w/ test runner
• Integrate w/ xharness when it's ready to ensure we can get results out
• Modify the build so that we can run locally and send the right things to helix