Generic warning location tests (dotnet#3146)

Adds a test which focused on warnings produced due to annotated generic parameters. This is relatively tricky for the product to deal with since it's often part of the type system and not code. So this test focused on all the different situations such warning can occur and the location where the warning is generated.

Co-authored-by: Tlakaelel Axayakatl Ceja <[email protected]>

test/ILLink.RoslynAnalyzer.Tests/generated/ILLink.RoslynAnalyzer.Tests.Generator/ILLink.RoslynAnalyzer.Tests.TestCaseGenerator/DataFlowTests.g.cs

@@ -7,6 +7,12 @@ namespace ILLink.RoslynAnalyzer.Tests
 	public sealed partial class DataFlowTests : LinkerTestBase
 	{
 
+		[Fact]
+		public Task GenericParameterWarningLocation ()
+		{
+			return RunTest (allowMissingWarnings: true);
+		}
+
 		[Fact]
 		public Task MethodByRefParameterDataFlow ()
 		{

test/Mono.Linker.Tests.Cases/DataFlow/GenericParameterDataFlow.cs

@@ -1,4 +1,7 @@
-using System;
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;