test: disable schema fetching in tarantool connection object

This would sometimes result in exceptions being thrown if a call was
made in the middle of a schema change.

test/conftest.py

@@ -282,6 +282,8 @@ class Instance:
             self.port,
             socket_timeout=timeout,
             connection_timeout=timeout,
+            connect_now=True,
+            fetch_schema=False,
         )
         try:
             yield c

test/int/test_joining.py

@@ -132,7 +132,7 @@ def test_replication(cluster: Cluster):
                 "return box.space._pico_instance:get(...):tomap()",
                 instance.instance_id,
             )[0]
-            space_cluster = conn.select("_cluster")
+            space_cluster = conn.call("box.space._cluster:select")
 
         expected = {
             "instance_id": instance.instance_id,
@@ -146,7 +146,7 @@ def test_replication(cluster: Cluster):
         }
         assert {k: v for k, v in raft_instance.items() if k in expected} == expected
 
-        assert list(space_cluster) == [
+        assert list(*space_cluster) == [
             [1, i1.instance_uuid()],
             [2, i2.instance_uuid()],
         ]