The class used to look at the x86_64 specific exception code to figure
out what kind of page fault happend, however this refactor allows
aarch64 to use the same class.
A lot of interrupt numbers are initialized with the unhandled interrupt
handler. Whenever a new handler is registered on one of these
interrupts, the old handler is unregistered first. Let's not be verbose
about this since it is perfectly normal.
If a page fault occurs while interrupts are disabled, we were wrongly
enabling interrupts right away in the page fault handler.
Instead, we should only do this if interrupts were enabled when the
page fault occurred.
