vite build --watch should check emptyOutDir

[yunsii]

Describe the bug

emptyDir directly even if use emptyOutDir: false with vite build --watch. It will clear others resources not build by vite.

Reproduction

theprimone/violet@refactor/vite/package.json#L11

System Info

Output of npx envinfo --system --npmPackages vite,@vitejs/plugin-vue --binaries --browsers:

  System:
    OS: Linux 5.4 Ubuntu 18.04.5 LTS (Bionic Beaver)
    CPU: (12) x64 Intel(R) Core(TM) i7-10710U CPU @ 1.10GHz
    Memory: 10.98 GB / 12.33 GB
    Container: Yes
    Shell: 4.4.20 - /bin/bash
  Binaries:
    Node: 14.15.1 - /usr/local/bin/node
    Yarn: 1.22.10 - /usr/local/bin/yarn
    npm: 6.14.8 - /usr/local/bin/npm
  npmPackages:
    vite: ^2.2.1 => 2.2.1 

---

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[patak-dev]

Would you check if this PR: #3043 fixes your issue @theprimone ?

[yunsii]

Would you check if this PR: #3043 fixes your issue @theprimone ?

Yes, it should be ok 🧐

[yunsii]

Still not release...