Enable AOT (Ahead-of-Time) Compilation in Tests

[Arlodotexe]

Background

While the original "why" behind AoT being disabled in tests is lost or unknown, the "why" behind enabling it now is known.

We are in the process of collecting and fixing the NativeAoT issues in the toolkit.

Problem

We'd like to be able to test more of the codebase with AoT than the sample app provides.

We could use our test projects, but AoT would need to be enabled.

Solution

Due to the nature of tests using shared projects, we're not able to toggle AoT for them individually.

We'll have to either enable csproj support for tests (see #101) or enable aot in all test projects simultaneously.

We've made progress towards AoT recently, but the Gallery App can only tell us so much. We'll need the ability to validate AoT issues using unit tests to ensure proper coverage long-term.