jets: refcount fixes caught by a linter

[dozreg-toplud]

Some refcount bugs caught by a linter (WIP):

• bytestream.c: we lose retained octs_list;
• chacha: forgot to increment the refcount of retained wid, didn't test wid and dat for being atoms
• hmac: didn't test out for being a direct atom even though the code clearly assumes it; missing c3_w -> atom conversions
• mat/rub/scow: plain leaks
• shax: confusion between retained c and owned d
• slaw: leaks, assumptions that numname is a direct atom (so no u3k(year)) but no checks; better fix is to just get rid of leaks by not having generic macros
• urwasm: leaks in run_once, saner control flow which is more readable for a linter and a human;
• u3z_uniq: leaked key
• loss.c: an atom was used as direct with no check