Formulate and implement a plan for getting iOS WebKit Results onto the dashboard

[gsnedders]

On our 2024 roadmap we have "Formulate and implement a plan for getting iOS WebKit Results onto the dashboard".

Our current intention, as far as I'm aware, is to get results from WebKitTestRunner's iOS Simulator builds submitted to wpt.fyi.

There's a few reasons why we're not using Safari; to quote the minutes of the previous meeting (#20 (comment)):

Sam: Mobile Safari is only meaningful for stable and beta, because that's the cadence Apple ships it.
... Ref tests on Mobile Safari would be meaningless due to the inability to change the viewport size.

To get WebKitTestRunner on iOS Simulator submitting results from wptrunner we practically have a few steps here:

• Make wptrunner support WebKitTestRunner on iOS Simulator (including starting and managing simulators)
• Set up some CI to download a single WebKit revision and run WebKitTestRunner against that on iOS Simulator

In reality, I believe we actually are intending something slightly more drastic given current Azure Pipelines capacity, and to have a better comparison point between mobile and desktop. Thus I believe the plan is slightly more like:

• Migrate existing full runs of Safari & Safari Technology Preview to another CI system (maintained by Apple's WebKit team),
• Set up some CI to download a single WebKit revision and run WebKitTestRunner against that on macOS,
• Make wptrunner support WebKitTestRunner on iOS Simulator (including starting and managing simulators)
• Set up some CI to download a single WebKit revision and run WebKitTestRunner against that on iOS Simulator

I don't envision the work required to get WebKitTestRunner on iOS Simulator to be significant, but it does need to be done.