Remove Python 2 compatibility code

The driver requires Python 3.10+ so these compatibility shims are no longer needed:

- Remove try/except for Queue vs queue (use queue directly)
- Remove try/except for __builtin__ vs builtins (use builtins directly)
- Remove try/except for thread vs _thread (use _thread directly)
- Remove try/except for futures vs concurrent.futures (use concurrent.futures directly)
- Remove try/except for unittest2 vs unittest (use unittest directly)
- Replace deprecated imp.reload with importlib.reload

Author: dkropachev

tests/integration/long/test_large_data.py

@@ -12,10 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-try:
-    from Queue import Queue, Empty
-except ImportError:
-    from queue import Queue, Empty  # noqa
+from queue import Queue, Empty
 
 from struct import pack
 import logging, sys, traceback, time

tests/integration/standard/test_shard_aware.py

@@ -17,15 +17,9 @@
 from subprocess import run
 import logging
 
-try:
-    from concurrent.futures import ThreadPoolExecutor, as_completed
-except ImportError:
-    from futures import ThreadPoolExecutor, as_completed  # noqa
-
-try:
-    import unittest2 as unittest
-except ImportError:
-    import unittest  # noqa
+from concurrent.futures import ThreadPoolExecutor, as_completed
+
+import unittest
 import pytest
 
 from cassandra.cluster import Cluster

tests/integration/standard/test_use_keyspace.py

@@ -2,10 +2,7 @@
 import time
 import logging
 
-try:
-    import unittest2 as unittest
-except ImportError:
-    import unittest  # noqa
+import unittest
 
 from unittest.mock import patch
 

tests/unit/io/eventlet_utils.py

@@ -16,21 +16,15 @@
 import os
 import select
 import socket
-try:
-    import thread
-    import Queue
-    import __builtin__
-    #For python3 compatibility
-except ImportError:
-    import _thread as thread
-    import queue as Queue
-    import builtins as __builtin__
+import _thread as thread
+import queue as Queue
+import builtins as __builtin__
 
 import threading
 import ssl
 import time
 import eventlet
-from imp import reload
+from importlib import reload
 
 def eventlet_un_patch_all():
     """

tests/unit/test_protocol_features.py

@@ -1,7 +1,4 @@
-try:
-    import unittest2 as unittest
-except ImportError:
-    import unittest  # noqa
+import unittest
 
 import logging
 

tests/unit/test_shard_aware.py

@@ -12,10 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-try:
-    import unittest2 as unittest
-except ImportError:
-    import unittest  # noqa
+import unittest
 
 import logging
 from unittest.mock import MagicMock