test: turn sspi-ffi-attacker into tests runnable with miri

[TheBestTvarynka]

Hi,
In the scope of this PR, I've refactored the sspi-fii-attacker:

1. Removed the sspi-ffi-attacker.
2. Moved scenarios to ffi/sspi/sec_handle/tests.
   Now we can run those scenarios with Miri which will help us catch UBs and other memory errors.
3. Fixed two UBs.

Additional context: #261 (comment)

[TheBestTvarynka]

It was fun to investigate and fix. In short, conversions chain like this one *mut SecPkgInfoW -> &mut SecPkgInfoW -> *mut SecPkgInfoW can create UB 😮

When we create &mut SecPkgInfoW, Rust creates a SharedReadWrite tag (it relates to stacked borrows and so on). And when we convert it to the raw pointer and try to deallocate, we have UB.
This is why I removed the conversion into &mut SecPkgInfoW and refactored it to use only raw pointers

[CBenoit]

Good job!

[CBenoit]

question/nitpick: Should we use the PSecPkgInfoW type alias? Remove it?

[TheBestTvarynka]

We are not allowed to implement the From trait for any raw pointers, because all raw pointers are foreign types

[CBenoit]

Sorry, I meant this:

Suggested change

	pub struct RawSecPkgInfoW(pub *mut SecPkgInfoW);
	pub struct RawSecPkgInfoW(pub PSecPkgInfoW);

I am under the impression that we don’t really use this alias.

[CBenoit]

Very nice! LGTM!

[CBenoit]

Merging now, the remaining comment is not very important