chore: addresses leftover from #44045 (#44080)

## 📖 What's in there?

Yesterday we didn't had time to address leftovers from #44045.
Here it is.

- [ ] 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 (from [PR
43814](#43814))
- [ ] 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)

## 🧪  How to test?

Several tests cases added:
- in dev mode, errors and warning: `NEXT_TEST_MODE=dev pnpm testheadless
--testPathPattern edge-configurable-runtime`
- in build mode, build error for pages on the `edge`:
`NEXT_TEST_MODE=start pnpm testheadless --testPathPattern
edge-configurable-runtime`

Co-authored-by: JJ Kasper <jj@jjsweb.site>

packages/next/src/build/analysis/get-page-static-info.ts

@@ -313,17 +313,14 @@ export async function getPageStaticInfo(params: {
       !isEdgeRuntime(resolvedRuntime)
     ) {
       const options = Object.values(SERVER_RUNTIME).join(', ')
-      if (typeof resolvedRuntime !== 'string') {
-        Log.error(
-          `The \`runtime\` config must be a string. Please leave it empty or choose one of: ${options}`
-        )
+      const message =
+        typeof resolvedRuntime !== 'string'
+          ? `The \`runtime\` config must be a string. Please leave it empty or choose one of: ${options}`
+          : `Provided runtime "${resolvedRuntime}" is not supported. Please leave it empty or choose one of: ${options}`
+      if (isDev) {
+        Log.error(message)
       } else {
-        Log.error(
-          `Provided runtime "${resolvedRuntime}" is not supported. Please leave it empty or choose one of: ${options}`
-        )
-      }
-      if (!isDev) {
-        process.exit(1)
+        throw new Error(message)
       }
     }
 
@@ -346,10 +343,10 @@ export async function getPageStaticInfo(params: {
       !isAPIRoute(page.replace(/^\/pages\//, '/'))
     ) {
       const message = `Page ${page} provided runtime 'edge', the edge runtime for rendering is currently experimental. Use runtime 'experimental-edge' instead.`
-      Log.error(message)
-
-      if (!isDev) {
-        process.exit(1)
+      if (isDev) {
+        Log.error(message)
+      } else {
+        throw new Error(message)
       }
     }
 

test/e2e/edge-configurable-runtime/index.test.ts

@@ -122,7 +122,7 @@ describe('Configurable runtime for pages and API routes', () => {
         expect(output.code).toBe(1)
         expect(output.stderr).not.toContain(`Build failed`)
         expect(output.stderr).toContain(
-          `error - Page / provided runtime 'edge', the edge runtime for rendering is currently experimental. Use runtime 'experimental-edge' instead.`
+          `Error: Page / provided runtime 'edge', the edge runtime for rendering is currently experimental. Use runtime 'experimental-edge' instead.`
         )
       })
     })