Add some WAIT for tests using replication

Author: byroot

test/cluster_client_replicas_test.rb

@@ -13,6 +13,11 @@ def test_client_can_command_with_replica
       assert_equal 'OK', r.set("key#{i}", i)
     end
 
+    begin
+      r.wait(6, 5_000)
+    rescue Redis::TimeoutError
+    end
+
     100.times do |i|
       assert_equal i.to_s, r.get("key#{i}")
     end
@@ -30,6 +35,11 @@ def test_some_reference_commands_are_sent_to_slaves_if_needed
 
     5.times { |i| r.set("key#{i}", i) }
 
+    begin
+      r.wait(6, 5_000)
+    rescue Redis::TimeoutError
+    end
+
     assert_equal %w[key0 key1 key2 key3 key4], r.keys
     assert_equal 5, r.dbsize
   end