Rationalizing existing NUNit test suites for the compiler

[cartermp]

We currently have two separate test NUnit test projects for the compiler:

FSharp.Compiler.UnitTests: https://github.com/dotnet/fsharp/tree/master/tests/FSharp.Compiler.UnitTests

FSharpSuite.Tests: https://github.com/dotnet/fsharp/blob/master/tests/fsharp/FSharpSuite.Tests.fsproj

I don't see too many meaningful differences between the two. Should these be merged into one? Or should better names be picked if there's a meaningful difference? Currently I don't know where I should stick a new compiler unit test.

[cartermp]

Related to #7075 - arguably this is a prerequisite.

[cartermp]

@TIHan any preferences?

[forki]

Ok. Which one should be the survivor?

[cartermp]

The one with the better name 😄

[TIHan]

Originally I started doing tests in Compiler.UnitTests, but I had to move it out and into FSharpSuite to take advantage of its rules to figure out where the paths to certain things are. After looking at it again, I think we could move some of them back (we don't have very many).

Ideally, it would all live in Compiler.UnitTests.

Also, we should start looking into how to be like Roslyn when it comes to testing this stuff.

[cartermp]

Okay. Let's bless Compiler.UnitTests and see if we can move some of the helper stuff over.

[cartermp]

@vzarytovskii and friends are working towards a plan that addresses the question here, will close