Drop unsupported Python fallback

We only support Python 3.6+

tests/src/python/test_qgsdelimitedtextprovider.py

@@ -30,10 +30,7 @@ import inspect
 import time
 import test_qgsdelimitedtextprovider_wanted as want  # NOQA
 
-try:
-    from collections.abc import Callable
-except ImportError:
-    from collections import Callable
+from collections.abc import Callable
 
 rebuildTests = 'REBUILD_DELIMITED_TEXT_TESTS' in os.environ
 

tests/src/python/test_qgspallabeling_base.py

@@ -23,11 +23,7 @@ import sys
 import datetime
 import glob
 import shutil
-
-try:
-    from collections.abc import Callable
-except ImportError:
-    from collections import Callable
+from collections.abc import Callable
 
 from qgis.PyQt.QtCore import QSize, qDebug, Qt
 from qgis.PyQt.QtGui import QFont, QColor