In #11568 we removed the NOSCRIPT flag from commands and keep the BLOCKING flag.
Aiming to allow them in scripts and let them implicitly behave in the non-blocking way.
In that sense, the old behavior was to allow LPOP and reject BLPOP, and the new behavior,
is to allow BLPOP too, and fail it only in case it ends up blocking.
So likewise, so far we allowed XREAD and rejected XREAD BLOCK, and we will now allow
that too, and only reject it if it ends up blocking.
77a65e82b2