Fix static SetAssemblyDescriptorResolver usage in tests

tests/Avalonia.Base.UnitTests/AssetLoaderTests.cs

@@ -7,7 +7,7 @@ using Xunit;
 
 namespace Avalonia.Base.UnitTests;
 
-public class AssetLoaderTests
+public class AssetLoaderTests : IDisposable
 {
     public class MockAssembly : Assembly {}
 
@@ -15,7 +15,7 @@ public class AssetLoaderTests
 
     private const string AssemblyNameWithNonAscii = "Какое-то-название";
 
-    static AssetLoaderTests()
+    public AssetLoaderTests()
     {
         var resolver = Mock.Of<IAssemblyDescriptorResolver>();
 
@@ -39,7 +39,7 @@ public class AssetLoaderTests
         Assert.Equal(AssemblyNameWithWhitespace, assemblyActual?.FullName);
     }
 
-    [Fact(Skip = "RegisterResUriParsers breaks this test. Investigate.")]
+    [Fact(Skip = "RegisterResUriParsers breaks this test. See https://github.com/AvaloniaUI/Avalonia/issues/2555.")]
     public void AssemblyName_With_Non_ASCII_Should_Load_Avares()
     {
         var uri = new Uri($"avares://{AssemblyNameWithNonAscii}/Assets/something");
@@ -60,4 +60,9 @@ public class AssetLoaderTests
         Mock.Get(descriptor).Setup(x => x.Assembly).Returns(assembly);
         return descriptor;
     }
+
+    public void Dispose()
+    {
+        AssetLoader.SetAssemblyDescriptorResolver(new AssemblyDescriptorResolver());
+    }
 }