[ plugin-legacy ] 页面内import worker 。构建后，chunk或者 assets目录内并没有生成work文件（已定位问题为使用plugin-legacy导致）

[dang0705]

Describe the bug

import Worker from '@XXX/worker/down-count?worker';

开发源码

生产报错

开发环境 下正常, 构建后生产环境找不到dow-count.js 并报错。进入dist后，也没有生成down-count相关的chunk

### 2022-07-25 问题已定位，在使用 plugin-legacy 的情况下，会出现上述问题，注释legacy代码，worker正常打包

Reproduction

git@gitee.com:henry-the-great/vite_worker_bug.git

System Info

System:
    OS: Windows 7
    Memory: 12GB
  Binaries:
    Node: 16.3 - C:\Program Files\nodejs\node.EXE
    npm: 7.24.2 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    chorme: 103.0.5060.134
    
  npmPackages:
    @vitejs/plugin-vue: ^3.0.1 => 3.0.1
    vite: ^3.0.2 => 3.0.2

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[github-actions]

Hello @dang0705. Please provide a minimal reproduction using a GitHub repository or StackBlitz. Issues marked with need reproduction will be closed if they have no activity within 3 days.

[sapphi-red]

It seems it happens with plugin-legacy + worker as you said.
Minimal reproduction: https://stackblitz.com/edit/vitejs-vite-nzeh9i?file=package.json