SA14/Tests: Remove masking the resultproxy and fix setup of fake cursors

Beforehand, after observing errors like::

  RuntimeError: number of values in row (1) differ from number of column processors (0)

we decided to take the `resultproxy` out of the equation in order to
work on the real gist of SQLAlchemy 1.4 compatibility.

When looking at this again, it turned out that the root cause have been
inaccuracies when setting up fake cursors within the test cases.
SQLAlchemy <1.4 might have been more forgiving on that, but >=1.4 isn't.

Author: amotl

src/crate/client/sqlalchemy/dialect.py

@@ -22,11 +22,6 @@
 import logging
 from datetime import datetime, date
 
-# FIXME: Workaround to be able to use SQLAlchemy 1.4.
-#        Caveat: This purges the ``cresultproxy`` extension
-#        at runtime, so it will impose a speed bump.
-import crate.client.sqlalchemy.monkey  # noqa:F401, lgtm[py/unused-import]
-
 from sqlalchemy import types as sqltypes
 from sqlalchemy.engine import default, reflection
 from sqlalchemy.sql import functions

src/crate/client/sqlalchemy/monkey.py

@@ -138,7 +138,7 @@ def test_assign_null_to_object_array(self):
     @patch('crate.client.connection.Cursor', FakeCursor)
     def test_assign_to_craty_type_after_commit(self):
         session, Character = self.set_up_character_and_cursor(
-            return_value=[('Trillian', None, None)]
+            return_value=[('Trillian', None)]
         )
         char = Character(name='Trillian')
         session.add(char)