Add Emit2 test project

[RikkiGibson]

Closes #57226

See https://github.com/dotnet/roslyn/runs/3944469911 for proof that the tests run in CI :)

cc @dotnet/roslyn-compiler

[jaredpar]

Can we link to the issue which inspired this and has the reasons for why we need yet another Emit test project here?

[333fred]

Please look through our scripts and add this test where appropriate (such as https://github.com/dotnet/roslyn/blob/main/eng/build.ps1#L333)

[RikkiGibson]

Did a search for CSharp\.Emit\.UnitTests and CSharp.Emit.UnitTests, adding parallel entries for Emit2. Any further suggestions on what to search for/update?

[333fred]

Is there anything special we need to do to mark the test project as non-shipping? Or is the whole test folder automatically marked as such?

[RikkiGibson]

Is there anything special we need to do to mark the test project as non-shipping? Or is the whole test folder automatically marked as such?

It appears that some Arcade configuration sees that the project name ends with UnitTests and sets the 'IsUnitTestProject' property which sets the 'IsShipping=false' property.

https://github.com/dotnet/arcade/blob/5a11ca12dac8353d469045ee794dc54f0ddd49a2/src/Microsoft.DotNet.Arcade.Sdk/tools/Tests.props#L15

https://github.com/dotnet/arcade/blob/main/Documentation/ArcadeSdk.md#isshipping-isshippingassembly-isshippingpackage-isshippingvsix-bool

I verified in the binlog that 'IsShipping' is false for the new project.

[jcouv]

Just curious, what does this list do (if you know)?

[chsienki]

Its the list of tests that are considered 'compiler' so you can run just the compiler tests without everything else.

[333fred]

Which then controls what the IOperation hook is run on.

[jcouv]

LGTM Thanks (iteration 5)