* fs.mitm: skeleton the use of special allocation in romfs build

* pm: add api for ams.mitm to steal application memory

* pm/mitm: okay, that api won't work, try a different one

* romfs: revert memory usage increases; we'll handle torture games case-by-case.

* pm/romfs: first (broken?) pass at dynamic heap.

I cannot wait to figure out all the ways this is wrong.

* Release the dynamic heap a little more eagerly

* romfs: animal crossing is also not a nice game

* romfs: fix issues in close-during-build

* romfs: zelda is a blight upon this earth

This is needed for Animal Crossing 2.0.0, which has >99000 fucking files.

We now do several passes over dir/file tables instead of one pass,
doing entire hash tables before we touch dir/file tables. Thus we
no longer need to simultaneously allocate hash table and dir/file table space.

In addition, we now do repeated passes building a segment of hash tables
at a time, when insufficient memory is available. Similar is also now the
case for file/dir tables, we try 0x40000 work buffer and divide by 2
until we successfully alloc. We don't allow a work buffer <0x4000, for
write/perf reasons. If a game triggers that, let me know I guess.

Hard to imagine a worse torture-test for this code than animal crossing.