Re-quarantine RazorRuntimeCompilationHostingStartupTest (issue #56553)

RazorViews_CanBeServedAndUpdatedViaRuntimeCompilation and
RazorPages_CanBeServedAndUpdatedViaRuntimeCompilation were unquarantined
in #66492 but have been failing again in CI immediately after the
unquarantine commit landed on main (builds 1398790, 1398958, 1399225,
1399308).

The tests are failing with a Xunit.Sdk.EqualException in the
'cached compilation' check (Assert-3): after requesting the same page
with no file changes, the test gets a different assembly name,
indicating the page is being spuriously recompiled.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

src/Mvc/test/Mvc.FunctionalTests/RazorRuntimeCompilationHostingStartupTest.cs

@@ -49,6 +49,7 @@ public override void Dispose()
     public HttpClient Client { get; private set; }
 
     [Fact]
+    [QuarantinedTest("https://github.com/dotnet/aspnetcore/issues/56553")]
     public async Task RazorViews_CanBeServedAndUpdatedViaRuntimeCompilation()
     {
         // Arrange
@@ -86,6 +87,7 @@ public async Task RazorViews_CanBeServedAndUpdatedViaRuntimeCompilation()
     }
 
     [Fact]
+    [QuarantinedTest("https://github.com/dotnet/aspnetcore/issues/56553")]
     public async Task RazorPages_CanBeServedAndUpdatedViaRuntimeCompilation()
     {
         // Arrange