Use correct temporary folder for solutions created in integration tests

src/VisualStudio/IntegrationTest/TestUtilities/IntegrationHelper.cs

@@ -80,7 +80,7 @@ public static void DeleteDirectoryRecursively(string path)
 
         public static string CreateTemporaryPath()
         {
-            return Path.Combine(Path.GetTempPath(), Path.GetRandomFileName());
+            return Path.Combine(TempRoot.Root, Path.GetRandomFileName());
         }
 
         public static bool DetachThreadInput(uint idAttach, uint idAttachTo)