Move to use interfaces, that will let us later add tests that will
verify that all the correct logging is performed. As an example, added a
test for XmlResultParser that ensures that the failures are correctly
generated. The test uses Moq to pass the different paths to be used and
later be able to verify the wirtten xml.
Harness.AutoConfigureMac now loads all the mac test projects both when
configuring and running tests, the only difference is that the test projects
that must be generated are only generated when configuring. This means that
the Harness.MacTestProject list contains the exact same test projects both
when configuring and when running tests.
This made it possible to remove logic to clone (mac) test projects the Jenkins
class (since Harness.MacTestProjects contains all the test projects already).
Consolidate logic to generate (mac) test projects:
* First we generate BCL and mono-native projects from their templates.
* Then we generate Full/System variations of any project that needs it.
This way we can remove logic to generate Full/System variations from the logic
to generate BCL/mono-native projects, which means less duplicated (and less
confusing) code.
To this purpose, significant changes were required:
* MacTestProject.TargetFrameworkFlavor has been modified to contain a bit mask
of the variations to generate.
* MacMonoNativeInfo has been significantly simplified, and some of the
generated code has been moved to the actual template instead.
* Some project generation (in MacTarget) to make things work as expected.
Fixes https://github.com/xamarin/xamarin-macios/issues/6322.