[Bug] Integration tests visit application and index routes

I'm opening this here although it may more properly belong in either @ember/test-helpers, ember-cli, or ember-qunit. It's unclear which holds responsibility. As this is an "out of the box" behavior I've opened the issue here. Feel free to transfer it if another repository makes more sense.

### 🐞 Describe the Bug

When creating an integration test using `module` and `setupRenderingTest`, the application's `application` and `index` route will be visited, for instance with the very basic test below:

```js
import { module, test } from "qunit";
import { setupRenderingTest } from "ember-qunit";
import { render } from "@ember/test-helpers";
import { hbs } from "ember-cli-htmlbars";

module("Integration | Component | expand-btn", function (hooks) {
setupRenderingTest(hooks);

test("it renders", async function (assert) {
await render(hbs``);

assert.equal(this.element.textContent.trim(), "");
});
});

```

### 🔬 Minimal Reproduction

Generate a new app, add logging to the application beforeModel and index beforeModel route hooks. Generate a component and run tests, observe the logging.

### 😕 Actual Behavior

Routes are visited even though the `visit` API has not been used.

### 🤔 Expected Behavior

No routes to be visited.

### 🌍 Environment

ember-source 3.24.2
ember-cli: 3.28.2
@ember/test-helpers: 2.5.0
ember-qunit: 5.1.5
node: 14