[E2E] Use NodeJS `http` module for Cypress backend (#25952)

frontend/test/__runner__/cypress-runner-backend.js

@@ -5,7 +5,7 @@ const { spawn } = require("child_process");
 const os = require("os");
 const path = require("path");
 
-const fetch = require("isomorphic-fetch");
+const http = require("http");
 
 const CypressBackend = {
   createServer(port = 4000) {
@@ -107,9 +107,30 @@ const CypressBackend = {
     }
 
     async function isReady(host) {
+      // This is needed until we can use NodeJS native `fetch`.
+      function request(url) {
+        return new Promise((resolve, reject) => {
+          const req = http.get(url, res => {
+            let body = "";
+
+            res.on("data", chunk => {
+              body += chunk;
+            });
+
+            res.on("end", () => {
+              resolve(JSON.parse(body));
+            });
+          });
+
+          req.on("error", e => {
+            reject(e);
+          });
+        });
+      }
+
       try {
-        const { status } = await fetch(`${host}/api/health`);
-        if (status === 200) {
+        const { status } = await request(`${host}/api/health`);
+        if (status === "ok") {
           return true;
         }
       } catch (e) {}