fix: correctly sort test scripts in package.json

The previous `keyOrder` referred to the legacy `test` & `e2e` commands
that were removed / deprecated since 3.0 stable

(cherry picked from commit 0ca37b7)

Author: haoqunjiang

packages/@vue/cli/lib/Generator.js

@@ -170,8 +170,8 @@ module.exports = class Generator {
     this.pkg.scripts = sortObject(this.pkg.scripts, [
       'serve',
       'build',
-      'test',
-      'e2e',
+      'test:unit',
+      'test:e2e',
       'lint',
       'deploy'
     ])