Re-enable log-impl tests

[todo]

https://github.com/roblabla42/KFS/blob/84f52da4950ee96188e38618b55d975a53609284/kernel/src/log_impl/filter/mod.rs#L365-L369

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This issue was generated by todo based on a TODO comment in 84f52da when #63 was merged. cc @Orycterope.

[Orycterope]

Eh whatever, the logger will not be in kernel in the end, so we would be better of ignoring this issue and closing it. Vote 👀 if you agree.

[roblabla]

We'll still want a kernel logger for debugging purposes.

[Orycterope]

Yeah, but does it need to be tested ? Will we be using log_impl in the long term ?

[roblabla]

Why shouldn't it be? And yes, I do think we'll keep using log_impl long-term.