Remove IVTs to legacy language service

[cartermp]

Moved the dead code paths to no longer be IVT into FSharp.Compiler.Private.

[cartermp]

I have no clue what the ever loving hell this test does and why but it's failing:

fsharp/vsintegration/tests/UnitTests/LegacyLanguageService/Tests.LanguageService.General.fs

Lines 106 to 120 in 027e8c9

	member public this.``PublicSurfaceArea.DotNetReflection``() =
	let ps = publicTypesInAsm @"FSharp.ProjectSystem.FSharp.dll"
	Assert.AreEqual(1, ps) // BuildPropertyDescriptor
	let ls = publicTypesInAsm @"FSharp.LanguageService.dll"
	Assert.AreEqual(0, ls)
	let compis = publicTypesInAsm @"FSharp.Compiler.Interactive.Settings.dll"
	Assert.AreEqual(5, compis)
	let compserver = publicTypesInAsm @"FSharp.Compiler.Server.Shared.dll"
	Assert.AreEqual(0, compserver)
	let lsbase = publicTypesInAsm @"FSharp.LanguageService.Base.dll"
	Assert.AreEqual(0, lsbase)
	let psbase = publicTypesInAsm @"FSharp.ProjectSystem.Base.dll"
	Assert.AreEqual(17, psbase)
	let fsi = publicTypesInAsm @"FSharp.VS.FSI.dll"
	Assert.AreEqual(1, fsi)

[cartermp]

I modified the code to use the public API for the information it needs and removed the test in question. I can't for the life of me understand the value in that test.

[KevinRansom]

@cartermp Well, the tests are a sort of cheap evaluation of whether public types have been added or removed from those assemblies. If public types are removed its potentially a breaking change, if they are added it's potentially an unintentional increase in surface are.

But that test does the job in a pretty bad way. And probably adds little value.

[cartermp]

Yeah, in this case I don't think they're of value here because the primary things they're testing are now dead code paths anyways