Fix use of wrong URL

lib/testing-utils.js

@@ -56,9 +56,6 @@ function setupTests(test) {
         // process.env only has strings fields, so a shallow copy is fine.
         t.context.env = {};
         Object.assign(t.context.env, process.env);
-        // Any test that runs code that expects to only be run on actions
-        // will depend on various environment variables.
-        process.env['GITHUB_API_URL'] = 'https://github.localhost/api/v3';
     });
     typedTest.afterEach.always(t => {
         // Restore stdout and stderr