Fix region prioritization in dump_process_memory.

[grrrrrrrrr]

dump_process_memory::sort_by_priority contained two algorithmic flaws:

1. When iterating over sorted offsets, regions preceding the current
   offset were popped and placed at the back with deque.push_back.
   Because these regions were consumed from the iterator, subsequent
   offset iterations could no longer match them, dropping regions from
   consideration and scrambling the non-priority region order.
2. Matched priority regions were prepended using deque.push_front,
   which reversed the requested relative priority order when multiple
   priority offsets matched distinct regions.

This change refactors the function to partition the memory regions into
priority and non-priority collections by checking whether any address in
offsets falls within [start_address, end_address) using binary search,
preserving the original monotonic address order for both groups.