build: run e2e tests on circlci (#13643)

test/protractor.conf.js

@@ -36,14 +36,8 @@ exports.config = {
   capabilities: {
     browserName: 'chrome',
 
-    chromeOptions: {
-      // Inside of Travis, we need to specify `--no-sandbox` because otherwise Chrome cannot
-      // be launched properly due to insufficient permissions in a non-sudo environment.
-      args: process.env['TRAVIS'] ? ['--no-sandbox'] : [],
-    },
-
     // Enables concurrent testing in the Webdriver. Currently runs three e2e files in parallel.
     shardTestFiles: true,
-    maxInstances: 3,
+    maxInstances: 5,
   }
 };