recv_sys_t::free_corrupted_page(): Renamed from recv_recover_corrupt_page().

recv_sys_t::is_memory_exhausted(): Renamed from recv_sys_heap_check().

recv_sys_t::max_blocks(): Accessor for max_log_blocks.

recv_sys_t::blocks: Buffer pool blocks reserved for redo log records.

For the debug functions related to recv_sys_t::alloc(), use the
logical name free().

Rename some variables 'store_to_hash' to 'store', because recv_sys.pages
is not a hash table.