is_sharing_with_others API was never really put to use properly since
it was introduced. The only place where it is used in Interrupts.cpp is
in conjuction with is_shared_handler() which is only true for
SharedIRQHandler and is_sharing_with_others will always return false.
Remove that API.
The handling of page tables is very architecture specific, so belongs
in the Arch directory. Some parts were already architecture-specific,
however this commit moves the rest of the PageDirectory class into the
Arch directory.
While we're here the aarch64/PageDirectory.{h,cpp} files are updated to
be aarch64 specific, by renaming some members and removing x86_64
specific code.
These instances were detected by searching for files that include
AK/Memory.h, but don't match the regex:
\\b(fast_u32_copy|fast_u32_fill|secure_zero|timing_safe_compare)\\b
This regex is pessimistic, so there might be more files that don't
actually use any memory function.
In theory, one might use LibCPP to detect things like this
automatically, but let's do this one step after another.
