With init_tree_desc() widened in the prior commit, the
size_t-returning odb_read_object_peeled() call in
add_preferred_base() and odb_read_object() call in pbase_tree_get()
can both flow straight through to init_tree_desc() and into the
pbase_tree_cache. Widen pbase_tree_cache.tree_size and the two
local size variables to size_t, drop the size_st bridges, and drop
the two cast_size_t_to_ulong() shims.
This was the last pair of cast_size_t_to_ulong() call sites in
builtin/pack-objects.c, completing the >4 GiB-objects work in that
file that this branch and its predecessors have been pursuing.
Assisted-by: Opus 4.7
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
548312534b