fix(server): fix compatibility with rdb snapshot

[adiholden]

The bug: writing full sync cut opcode to rdb snapshot format breaks compatibility with rdb format

PR changes:
Do not write dfly full sync cut opcode for disk snapshot (not for df and not for rdb)
Add pytest for loading rdb snapshot generated by dragonfly with Redis server

[dranikpg]

First redis compatibility test 👍🏻

If more checks are needed, you can re-define dragonfly.ihash in redis. It's bit of a hassle, but doable 🙂

local dragonfly = {}
function draognfly.ihash(hash, sort, ...)
  local res = redis.pcall(arg)
  -- if sort, sort res
  -- use any hash function to res... lua really doesn't have one :(
end

[adiholden]

I wanted to use the seeder capture but got error
redis.exceptions.ResponseError: Error compiling script (new function): user_script:1: unexpected symbol near '#'

I want the fix to go to 1.19, so I will merge this now and can investigate more if we can do a simple change to make this work

[romange]

@adiholden you got an error with Redis, right?

[adiholden]

do you mean the script error? yes its in redis