We can run out of box reserved memory in vmpu_load_boxes, even when we actually have enough memory

We can run out of box reserved memory in vmpu_load_boxes, even when we actually have enough memory. This is because the amount reserved by the linkerscript for bss_boxes is only enough space if we optimally pack the box reserved memories (which may not be possible to do with certain alignment requirements); otherwise, we waste enough space when aligning a box reserved memory to its size as to overflow the available bss_boxes space.

Start at vmpu_load_boxes and the linker script reservation for bss_boxes; inspect how box-reserved memories are aligned and packed. Reproduce an overflow with non-optimal alignment, then verify that the reserved space remains sufficient without relying on optimal packing.

Written by the indexing model from the issue text.