try harder to set up s3_server fixture

it only happens once per session, so we may as well take the time

python/pyarrow/tests/conftest.py

@@ -192,7 +192,7 @@ def wrapper(*args, **kwargs):
 
 @pytest.fixture(scope='session')
 def s3_server(s3_connection, tmpdir_factory):
-    @retry(attempts=5, delay=0.1, backoff=2)
+    @retry(attempts=5, delay=1, backoff=2)
     def minio_server_health_check(address):
         resp = urllib.request.urlopen(f"http://{address}/minio/health/cluster")
         assert resp.getcode() == 200