recycle_waifs fix

[sorressean]

This PR contains logic fixes to recycle_waifs reproduction steps:

1. Load stock Lambdacore.
2. @create #1 called "generic waif",waif
3. @corify waif as waif
4. @verb waif:new tnt
5. @program waif:new
6. Paste the following code: set_task_perms(caller_perms()); w = new_waif(); w:initialize(); return w;
7. Once the verb saves, eval $waif:new(); Expected: E_VRBNF; got panic. The issue is that we were previously calling recycled_waifs:erase, which was invalidating the current iterator.
8. Create a vector which stores a list of all waifs to be recycled. After we mark them for recycle, iterate through that vector and free/remove them from the map.
9. I also took the opportunity to update the map on both recycled_waifs and waif_class_count to be an unordered_map. These are true hashes (and pointers can be hashed), so the amount of indexing and setting done will be sped up by a decent amount. reproduction steps:
10. Load stock Lambdacore.
11. @create #1 called "generic waif",waif
12. @corify waif as waif
13. @verb waif:new tnt
14. @program waif:new
15. Paste the following code: set_task_perms(caller_perms()); w = new_waif(); w:initialize(); return w;
16. Once the verb saves, eval $waif:new(); Expected: E_VRBNF; got panic. The issue is that we were previously calling recycled_waifs:erase, which was invalidating the current iterator.
17. Create a vector which stores a list of all waifs to be recycled. After we mark them for recycle, iterate through that vector and free/remove them from the map.
18. I also took the opportunity to update the map on both recycled_waifs and waif_class_count to be an unordered_map. These are true hashes (and pointers can be hashed), so the amount of indexing and setting done will be sped up by a decent amount.