Fix initialization of TokenOrIdentifierObject#transformFlags.

This should start with `TransformFlags.None` just like in the `Node`
constructor in `src/compiler/utilities.ts`.

src/services/services.ts

@@ -214,7 +214,7 @@ namespace ts {
             this.end = end;
             this.flags = NodeFlags.None;
             this.modifierFlagsCache = ModifierFlags.None;
-            this.transformFlags = undefined!; // TODO: GH#18217
+            this.transformFlags = TransformFlags.None;
             this.parent = undefined!;
         }