MEDIUM: init: initialize the trash earlier

MEDIUM: init: initialize the trash earlier

More and more utility functions rely on the trash while most of the init
code doesn't have access to it because it's initialized very late (in
PRE_CHECK for the initial one). It's a pool, and it purposely supports
being reallocated, so let's initialize it in STG_POOL so that early
STG_INIT code can at least use it.