Feat: set NoCow for Btrfs/Bcachefs

[MeowKatee]

Description:

KDiskMark should set NoCow (via chattr +C on the temp directory to place IO files for example) for bcachefs/btrfs for the test files

As far as I know, with Copy-on-Write enabled, the write performance will be slow down about 2x

[JonMagon]

Hello, I apologize for the very delayed response. I've checked, you're right - the random write speed is particularly affected. I'll need to think about the best way to implement this. Thank you for pointing it out.