When doing `$replica replicaof no one`, we may get a LOADING
error, this is because during the test execution, the replica
may reconnect very quickly, and the full sync is initiated,
and the replica has entered the LOADING state.
In this commit, we make sure the primary is pasued after the
fork, so the replica won't enter the LOADING state, and with
this fix, this test seems more natural and predictable.
Signed-off-by: Binbin <binloveplay1314@qq.com>
4aacffa32d