Now, the abstracted stack offsets grow in the same direction as
the real stack values in hardware, and allocating stack memory is done
by the taking the last stack offset, adding required abi size
and aligning to the required abi align. Stack handling is now more
natural as it aligns itself with how it works in hardware; hence
stepping through the debugger and printing out different stack
values is intuitive. Finally, the stack pointers are now correctly
aligned to the required (and not necessarily natural) alignment.