chore: update package dependency and remove temporary workaround code

Author: filzrev

tests/BenchmarkDotNet.Analyzers.Tests/Fixtures/AnalyzerTestFixture.cs

@@ -19,12 +19,6 @@ public abstract class AnalyzerTestFixture<TAnalyzer>
     private readonly CSharpAnalyzerTest<TAnalyzer, DefaultVerifier> _analyzerTest;
     private readonly DiagnosticDescriptor? _ruleUnderTest;
 
-    // TODO: Removed temporary workaround code when Microsoft.CodeAnalysis.CSharp.Analyzer.Testing package is updated. https://github.com/dotnet/roslyn-sdk/issues/1233
-    private static readonly Lazy<ReferenceAssemblies> lazyNet100 = new(() => new(
-        targetFramework: "net10.0",
-        referenceAssemblyPackage: new PackageIdentity("Microsoft.NETCore.App.Ref", "10.0.0"),
-        referenceAssemblyPath: Path.Combine("ref", "net10.0")));
-
     private AnalyzerTestFixture(bool assertUniqueSupportedDiagnostics)
     {
         _analyzerTest = new InternalAnalyzerTest