fuzzers: Use mimalloc and scudo in QEMU fuzzers

[langston-barrett]

Towards #3541. I targeted the libafl_qemu fuzzers first since they use a huge C library, which might make them more prone to memory corruption. They didn't use mimalloc already, wasn't sure if this was just an oversight?

[domenukk]

I'm not sure if the C part uses the rust allocator at all?

[langston-barrett]

I'm not sure if the C part uses the rust allocator at all?

Right, but it could overwrite e.g., heap metadata of the Rust allocations right? In any case, the Rust code certainly uses the allocator and benefits from additional safety.

[domenukk]

Mimalloc also has a feature that enables a bunch of security checks btw.

I don't think the extra security is needed but also cannot hurt :)

[langston-barrett]

Yeah, I wouldn't think of it so much in terms of security as in terms of extra protection against coding errors that result in memory corruption.

[0xalpharush]

Should this set these options https://source.android.com/docs/security/test/scudo? LLVM's default seem to effectively disable the mitigations