Add tests for server component HMR (#43779)

Something we haven't covered in our tests.

NEX-35

## Bug

- [ ] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Errors have a helpful link attached, see
[`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ]
[e2e](https://github.com/vercel/next.js/blob/canary/contributing/core/testing.md#writing-tests-for-nextjs)
tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see
[`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)

## Documentation / Examples

- [ ] Make sure the linting passes by running `pnpm build && pnpm lint`
- [ ] The "examples guidelines" are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)

test/e2e/app-dir/index.test.ts

@@ -378,6 +378,27 @@ describe('app dir', () => {
       }
     )
     ;(isDev ? describe : describe.skip)('HMR', () => {
+      it('should HMR correctly for server component', async () => {
+        const filePath = 'app/dashboard/index/page.js'
+        const origContent = await next.readFile(filePath)
+
+        try {
+          const browser = await webdriver(next.url, '/dashboard/index')
+          expect(await browser.elementByCss('p').text()).toContain(
+            'hello from app/dashboard/index'
+          )
+
+          await next.patchFile(
+            filePath,
+            origContent.replace('hello from', 'swapped from')
+          )
+
+          await check(() => browser.elementByCss('p').text(), /swapped from/)
+        } finally {
+          await next.patchFile(filePath, origContent)
+        }
+      })
+
       it('should HMR correctly for client component', async () => {
         const filePath = 'app/client-component-route/page.js'
         const origContent = await next.readFile(filePath)