v0.22 with c8 coverage does not clear tmp

[mmk0083]

Describe the bug

After upgrading to v0.22 we noticed each run of vitest was getting progressively slower. After awhile it stopped working entirely and would fail with an out of memory error. After some digging - it seems that the files in /coverage/tmp are not being cleared out between runs. Prior to v0.22 this was happening automatically and seems like it should be the default behavior per c8's documentation.

Reproduction

We are running vitest run --environment jsdom --coverage. After running - look in /coverage/tmp and note the number of .json files present. Each time you run, this folder gets larger.

System Info

System:
    OS: macOS 12.5.1
    CPU: (16) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 8.64 GB / 32.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 16.13.2 - ~/.nvm/versions/node/v16.13.2/bin/node
    npm: 8.1.2 - ~/.nvm/versions/node/v16.13.2/bin/npm
  Browsers:
    Chrome: 101.0.4951.54
    Firefox: 100.0.2
    Safari: 15.6.1
  npmPackages:
    @vitejs/plugin-vue: ^3.0.0 => 3.0.3 
    vite: ^3.0.0 => 3.0.9 
    vitest: ^0.22.1 => 0.22.1

Used Package Manager

npm

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[VividLemon]

I'm running "vitest": "^0.23.1" and this issue is still occurring.