Remove empty column related test fixes

Author: WillAyd

pandas/core/internals/blocks.py

@@ -2360,4 +2360,5 @@ def external_values(values: ArrayLike) -> ArrayLike:
         values.flags.writeable = False
 
     # TODO(CoW) we should also mark our ExtensionArrays as read-only
+
     return values

pandas/tests/frame/methods/test_dropna.py

@@ -187,7 +187,7 @@ def test_dropna_tz_aware_datetime(self):
         df = DataFrame()
         dt1 = datetime.datetime(2015, 1, 1, tzinfo=dateutil.tz.tzutc())
         dt2 = datetime.datetime(2015, 2, 2, tzinfo=dateutil.tz.tzutc())
-        df = DataFrame({"Time": [dt1]})
+        df["Time"] = [dt1]
         result = df.dropna(axis=0)
         expected = DataFrame({"Time": [dt1]})
         tm.assert_frame_equal(result, expected)