Add test case for #48506 (#48696)

Closes NEXT-228
Closes NEXT-227

test/e2e/app-dir/rsc-basic/app/app-react/page.js

@@ -0,0 +1,5 @@
+import React from 'react'
+
+export default function Page() {
+  return <div>{'version=' + React.version}</div>
+}

test/e2e/app-dir/rsc-basic/pages/pages-react.js

@@ -0,0 +1,5 @@
+import React from 'react'
+
+export default function Page() {
+  return <div>{'version=' + React.version}</div>
+}

test/e2e/app-dir/rsc-basic/rsc-basic.test.ts

@@ -433,6 +433,21 @@ describe('app dir - rsc basics', () => {
     expect(await res.text()).toBe('Hello from import-test.js')
   })
 
+  it('should use stable react for pages', async () => {
+    const resPages = await next.fetch('/pages-react')
+    const versionPages = (await resPages.text()).match(
+      /<div>version=([^<]+)<\/div>/
+    )?.[1]
+
+    const resApp = await next.fetch('/app-react')
+    const versionApp = (await resApp.text()).match(
+      /<div>version=([^<]+)<\/div>/
+    )?.[1]
+
+    expect(versionPages).not.toInclude('-next-')
+    expect(versionApp).toInclude('-next-')
+  })
+
   // disable this flaky test
   it.skip('should support partial hydration with inlined server data in browser', async () => {
     // Should end up with "next_streaming_data".