Fix integration tests, and razor, by using the correct cancellation token (#10301)

This reverts commit d76f5c5, humorously
entitled "Check correct CancellationToken". Sorry @DustinCampbell 😁

What was happening was that when a project change was queued up, we
cancelled any previous work that was in play. This used to check the
disposal cancellation token, so we didn't try to release a semaphore
that was disposed. The change to use the passed in cancellation token
meant we never released the semaphore.

Author: davidwengier

src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/ProjectWorkspaceStateGenerator.cs

@@ -109,6 +109,11 @@ public void CancelUpdates()
 
     private async Task UpdateWorkspaceStateAsync(Project? workspaceProject, IProjectSnapshot projectSnapshot, CancellationToken cancellationToken)
     {
+        if (_disposeTokenSource.IsCancellationRequested)
+        {
+            return;
+        }
+
         try
         {
             // Only allow a single TagHelper resolver request to process at a time in order to reduce
@@ -172,7 +177,7 @@ await _projectManager
             {
                 // Prevent ObjectDisposedException if we've disposed before we got here. The dispose method will release
                 // anyway, so we're all good.
-                if (!cancellationToken.IsCancellationRequested)
+                if (!_disposeTokenSource.IsCancellationRequested)
                 {
                     _semaphore.Release();
                 }