Skip conflicting test and re-enable WebHostBuilder test (#30672)

Author: John Luo

src/Hosting/Hosting/test/HostingApplicationDiagnosticsTests.cs

@@ -493,7 +493,7 @@ public void ActivityOnImportHookIsCalled()
             Assert.True(Activity.Current.Recorded);
         }
 
-        [Fact]
+        [Fact(Skip = "https://github.com/dotnet/aspnetcore/issues/30582")]
         public void ActivityListenersAreCalled()
         {
             var hostingApplication = CreateApplication(out var features);

src/Hosting/Hosting/test/WebHostBuilderTests.cs

@@ -15,7 +15,6 @@
 using Microsoft.AspNetCore.Hosting.Tests.Fakes;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
-using Microsoft.AspNetCore.Testing;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
@@ -115,7 +114,6 @@ public async Task MultipleUseStartupCallsLastWins(IWebHostBuilder builder)
 
         [Theory]
         [MemberData(nameof(DefaultWebHostBuildersWithConfig))]
-        [QuarantinedTest("https://github.com/dotnet/aspnetcore/issues/30582")]
         public async Task UseStartupFactoryWorks(IWebHostBuilder builder)
         {
             void ConfigureServices(IServiceCollection services) { }