Instead of using a volatile storage for the address environment in the
binfmt / loadinfo structures, always allocate the address environment
from kheap.
This serves two purposes:
- If the task creation fails, any kernel thread that depends on the
address environment created during task creation will not lose their
mappings (because they hold a reference to it)
- The current address environment variable (g_addrenv) will NEVER contain
a stale / incorrect value
- Releasing the address environment is simplified as any pointer given
to addrenv_drop() can be assumed to be heap memory
- Makes the kludge function addrenv_clear_current irrelevant, as the
system will NEVER have invalid mappings any more