Add scripts to run device tests

[mattleibow]

Description of Change

This PR adds the bits required to run the device tests - either from the terminal or on CI.

I am splitting each platform into separate cake files so that the arguments can be focused and easy to use. For example, the simplest case to run tests would be:

dotnet cake eng/devices/<platform>.cake --project=$PWD/xxx/xxx.csproj

For example:

dotnet cake eng/devices/ios.cake \
  --project=$PWD/src/Platform.Handlers/tests/Xamarin.Platform.Handlers.DeviceTests.iOS/Xamarin.Platform.Handlers.DeviceTests.iOS.csproj

dotnet cake eng/devices/android.cake \
  --project=$PWD/src/Essentials/test/DeviceTests.Android/Xamarin.Essentials.DeviceTests.Android.csproj 

There is also a way just to run an output app file without building the project, then use the --app argument:

dotnet cake eng/devices/<platform>.cake --project=$PWD/xxx/xxx.csproj

For example:

dotnet cake eng/devices/ios.cake \
  --app=$PWDsrc/Platform.Handlers/tests/Xamarin.Platform.Handlers.DeviceTests.iOS/bin/iPhoneSimulator/Release/XamarinEssentialsDeviceTestsiOS.app

There is either a way to do everything and build and run in one go, or you can decide:

• --target=test (default) - build and test
• --target=build - just build and not run
• --target=test --exclusive - just test and not run

In addition to what to do, you can specify more accurate paths:

• --project=<path-to-csproj> - the path to the platform .csproj file (required)
• --binlog=<path-to-binlog> - the path to store the binlog file of the build (default: xxx.csproj.binlog)
• --app=<pth-to-apk-or-app> - the path to the .app folder o the .apk file (default: the first app/apk in the bin directory)
• --results=<path-to-results-dir> - the path to a directory that will hold all the test results and device logs (default: xxx.app-results)
• --device=<device-combo> - the target ID of the device used by xharness in the form
  <platform>-<device|simulator|emulator>[-<32|64>][_<ios-version|android-api>]
  eg: ios-simulator-64_13.4,android-emulator-32_30,[...]
• --package=<android-package-name> - the Android app package name found in the manifest
• --instrumentation=<android-instrumentation-name> - the Android instrumentation name

Issues Resolved

• Fixes part of [Spec] Setup Platform Device Tests to use xHarness dotnet/maui#329

API Changes

None

Platforms Affected

None

Behavioral/Visual Changes

None

Before/After Screenshots

Not applicable

Testing Procedure

The cake files can just be run using either the default args or any set of valid, custom args. This should not require any other work - except maybe to install the emulators using the SDK manager. They are created, started and deleted after each run.

PR Checklist

• Targets the correct branch
• Tests are passing (or failures are unrelated)

[mattleibow]

Tis needs to be added to the CI yaml, but that should probably be done in a separate PR.

[rmarinho]

I wonder if the build of the project that we have in the other cake script should be used..

[mattleibow]

I wonder if the build of the project that we have in the other cake script should be used..

That can be done too. You can pass in the app package instead of the project and then add the --exclusive arg. This will skip the build and run the tests directly. We could potentially have a bunch of jobs that pop out different variants of some app, and then just run all the tests on each app.