Add missing calls to raxStop (#7532)

Since the dynamic allocations in raxIterator are only used for deep walks, memory
leak due to missing call to raxStop can only happen for rax with key names longer
than 32 bytes.

Out of all the missing calls, the only ones that may lead to a leak are the rax
for consumer groups and consumers, and these were only in AOFRW and rdbSave, which
normally only happen in fork or at shutdown.