Remove light-ups to get tests working

I don't so much care that someone with NRT will get duplicate diagnostics when returning null.

src/Microsoft.VisualStudio.Threading.Analyzers.CodeFixes/Microsoft.VisualStudio.Threading.Analyzers.CodeFixes.csproj

@@ -34,7 +34,7 @@
   </ItemDefinitionGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="2.9.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="2.8.2" />
     <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="2.9.6" PrivateAssets="all" />
     <PackageReference Include="MicroBuild.VisualStudio" Version="$(MicroBuildVersion)" />
     <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.3" />

src/Microsoft.VisualStudio.Threading.Analyzers.Tests/Helpers/VisualBasicCodeFixVerifier`2+Test.cs

@@ -36,7 +36,7 @@ public Test()
                     Project? project = solution.GetProject(projectId);
 
                     var parseOptions = (VisualBasicParseOptions)project!.ParseOptions!;
-                    project = project.WithParseOptions(parseOptions.WithLanguageVersion(LanguageVersion.VisualBasic16));
+                    project = project.WithParseOptions(parseOptions.WithLanguageVersion(LanguageVersion.VisualBasic15_5));
 
                     if (this.HasEntryPoint)
                     {

src/Microsoft.VisualStudio.Threading.Analyzers.Tests/Microsoft.VisualStudio.Threading.Analyzers.Tests.csproj

@@ -23,7 +23,7 @@
     <PackageReference Include="MicroBuild.VisualStudio" Version="$(MicroBuildVersion)" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.CodeFix.Testing.XUnit" Version="1.0.1-beta1.20209.1" />
     <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic.CodeFix.Testing.XUnit" Version="1.0.1-beta1.20209.1" />
-    <PackageReference Include="Microsoft.CodeAnalysis" Version="3.1.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis" Version="2.8.2" />
     <PackageReference Include="Microsoft.VisualStudio.OLE.Interop" Version="7.10.6070" />
     <PackageReference Include="Microsoft.VisualStudio.Shell.14.0" Version="14.3.25407" IncludeAssets="runtime" />
     <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.11.0" Version="11.0.61030" IncludeAssets="runtime" />

src/Microsoft.VisualStudio.Threading.Analyzers.Tests/VSTHRD114AvoidReturningNullTaskAnalyzerTests.cs

@@ -18,29 +18,27 @@ class Test
 {
     public Task<object> GetTaskObj()
     {
-        return null;
+        return [|null|];
     }
 }
 ";
             await new VerifyCS.Test
             {
                 TestCode = csharpTest,
-                ExpectedDiagnostics = { VerifyCS.Diagnostic().WithSpan(8, 16, 8, 20), },
             }.RunAsync();
 
             var vbTest = @"
 Imports System.Threading.Tasks
 
 Friend Class Test
     Public Function GetTaskObj() As Task(Of Object)
-        Return Nothing
+        Return [|Nothing|]
     End Function
 End Class
 ";
             await new VerifyVB.Test
             {
                 TestCode = vbTest,
-                ExpectedDiagnostics = { VerifyVB.Diagnostic().WithSpan(6, 16, 6, 32), },
             }.RunAsync();
         }
 
@@ -194,105 +192,5 @@ public Task<object> GetTaskObj(string s)
                 TestCode = test,
             }.RunAsync();
         }
-
-        [Fact]
-        public async Task NullableEnablePragmaBeforeClass_NoDiagnostic()
-        {
-            var test = @"
-using System.Threading.Tasks;
-
-#nullable enable
-
-class Test
-{
-    public Task<object> GetTaskObj(string s)
-    {
-        return null;
-    }
-}
-";
-            await new VerifyCS.Test
-            {
-                TestCode = test,
-                SolutionTransforms =
-                {
-                    (solution, projectId) =>
-                    {
-                        var project = solution.GetProject(projectId);
-                        var parseOptions = (CSharpParseOptions)project!.ParseOptions!;
-
-                        return project.WithParseOptions(parseOptions.WithLanguageVersion(LanguageVersion.CSharp8)).Solution;
-                    },
-                },
-            }.RunAsync();
-        }
-
-        [Fact]
-        public async Task NullableEnablePragmaBeforeMethod_NoDiagnostic()
-        {
-            var test = @"
-using System.Threading.Tasks;
-
-
-class Test
-{
-#nullable enable
-    public Task<object> GetTaskObj(string s)
-    {
-        return null;
-    }
-}
-";
-            await new VerifyCS.Test
-            {
-                TestCode = test,
-                SolutionTransforms =
-                {
-                    (solution, projectId) =>
-                    {
-                        var project = solution.GetProject(projectId);
-                        var parseOptions = (CSharpParseOptions)project!.ParseOptions!;
-
-                        return project.WithParseOptions(parseOptions.WithLanguageVersion(LanguageVersion.CSharp8)).Solution;
-                    },
-                },
-            }.RunAsync();
-        }
-
-        [Fact]
-        public async Task NullableEnablePragmaBeforeOnlySomeReturns_Diagnostic()
-        {
-            var test = @"
-using System.Threading.Tasks;
-
-class Test
-{
-    public Task<object> GetTaskObj(string s)
-    {
-        if (string.IsNullOrEmpty(s))
-        {
-            return [|null|];
-        }
-
-#nullable enable
-        return null;
-    }
-}
-";
-            await new VerifyCS.Test
-            {
-                TestCode = test,
-                SolutionTransforms =
-                {
-                    (solution, projectId) =>
-                    {
-                        var project = solution.GetProject(projectId);
-                        var parseOptions = (CSharpParseOptions)project!.ParseOptions!;
-
-                        return project.WithParseOptions(parseOptions.WithLanguageVersion(LanguageVersion.CSharp8)).Solution;
-                    },
-                },
-            }.RunAsync();
-        }
     }
 }