Use __fastfail in libpanic_abort on Windows

[rylev]

libpanic_abort currently uses Rust's abort intrinsic for aborts (which uses an illegal opcode to abort the process). This directly contrasts with libstd which uses inline assembly to call into Windows __failfail intrinsic. This is preferred because __fastfail allows for debuggers to attach after the process has aborted for debugging.

Perhaps we should use the same abort implementation used in libstd for libpanic_abort.

Drawbacks

Before Windows 8 __fastfail wasn't available and so calling into it on this platforms leads to an access violation. Access violations are not catchable by normal exception handlers but are catchable by [SEH}(https://docs.microsoft.com/en-us/windows/win32/debug/structured-exception-handling)

[retep998]

The current method of using intrinsics::abort is also an exception that can be caught by SEH. Therefore on platforms before Windows 8 __fastfail is no worse than intrinsics::abort, but on newer platforms it will ensure the process fails fast.

[rylev]

I'm going to open a PR for this which should hopefully push the discussion along.

[rylev]

@alexcrichton, can we reopen this issue so we can use it to track ARM support?