* gc.c: rename heap management functions with prefix "heap_".
* allocate_sorted_array() -> heap_allocate_sorted_array().
* slot_add_freeobj()      -> heap_slot_add_freeobj().
* assign_heap_slot()      -> heap_assign_slot().
* add_heap_slots()        -> heap_add_slots().
* init_heap()             -> heap_init().
* set_heap_increment()    -> heap_set_increment().
* gc.c (initial_expand_heap): inlined in rb_gc_set_params().



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42026 b2dd03c8-39d4-4d8f-98ff-823fe69b080e