test: simplify loadModule special case handling for tests

1. createRequire should have been properly handled in newer Jest
versions: jestjs/jest#9469
2. We don't test migrators with Jest mock modules anymore

So it's safe to skip that condition

Author: haoqunjiang

packages/@vue/cli-shared-utils/lib/module.js

@@ -62,10 +62,9 @@ exports.resolveModule = function (request, context) {
 }
 
 exports.loadModule = function (request, context, force = false) {
-  // createRequire doesn't work with jest mock modules
-  // (which we used in migrator for inquirer, and in tests for cli-service)
-  // TODO: it's supported in Jest 25
-  if (process.env.VUE_CLI_TEST && (request.endsWith('migrator') || context === '/')) {
+  // createRequire doesn't work with jest mocked fs
+  // (which we used in tests for cli-service)
+  if (process.env.VUE_CLI_TEST && context === '/') {
     return require(request)
   }