384 Build-templates files can not generated due to build procedure changed

[tangkaikk]

Cocos Creator version

384

System information

All

Issue description

1. First time build web-mobile, plugin will generate application.ejs, index.ejs under the folder build-templates, after build completion, nothing under the build-templates folder.
2. Second time build web-mobile, after build completion, there are appliction.js and index.js under the folder build-templates.

用户第一次建構時 (build-templates 是空的狀態下)
預計用插件來放入 build-templates 的 ejs 文件並沒有被建構到

第二次建構時, 因為第一次的關係
此時 build-templates 殘留著先前的 ejs 文件
這時建構後的 build 目錄才是我們自訂的 js 文件

Relevant error log output

No response

Steps to reproduce

1. First time build web-mobile, plugin will generate application.ejs, index.ejs under the folder build-templates, after build completion, nothing under the build-templates folder.
2. Second time build web-mobile, after build completion, there are appliction.js and index.js under the folder build-templates.

Minimal reproduction project

NewProject(4).zip

No response