fix RelayResolverModel-test

Summary: This test does not actually add the todo object to the `TODO_STORE` that it reads (and expects to exist), but the current implementation of `RelayReader` creates the todo record regardless so the test is passing. After the fix for T162471299 lands, we need the changes in this diff so that the test passes.

Reviewed By: voideanvalue

Differential Revision: D51436475

fbshipit-source-id: ac4ff215c9d2b7e14b2ac2359dbe038da7c20c87

packages/react-relay/__tests__/RelayResolverModel-test.js

@@ -333,6 +333,7 @@ describe.each([
         ? 'NULL!'
         : 'NOT NULL!';
     }
+    addTodo('Test todo');
 
     const renderer = TestRenderer.create(
       <EnvironmentWrapper environment={environment}>