update InteractiveIntroduceVariable test after..

.. new use var options. If you don't set options, you get default
options.

src/EditorFeatures/CSharpTest/Interactive/CodeActions/InteractiveIntroduceVariableTests.cs

@@ -123,7 +123,7 @@ public static void Main()
     {
         for (int i = 0; i < 10; i++)
         {
-            var {|Rename:v|} = i + 1;
+            int {|Rename:v|} = i + 1;
             Console.WriteLine(v);
         }
     }