This reverts commit 96d4120ac08db3f2d566e8e5c3bc134a24aa0afc.
ivsalloc() depends on chunks_rtree being initialized. This can be
worked around via a NULL pointer check. However,
thread_allocated_tsd_get() also depends on initialization having
occurred, and there is no way to guard its call in free() that is
cheaper than checking whether ptr is NULL.