Corrected the error classes inspected for the "is_disconnect" check for the
``mariadbconnector`` dialect, which was failing for disconnects that
occurred due to common MySQL/MariaDB error codes such as 2006; the DBAPI
appears to currently use the ``mariadb.InterfaceError`` exception class for
disconnect errors such as error code 2006, which has been added to the list
of classes checked.

For the current "real reconnect test", shutting down the mariadb
connection from the client side produces
ProgrammingError("Connection isn't valid anymore") which we also
continue to intercept.

Fixes: #7457
Change-Id: I0b37cd7a73359a23ad756ff2af0a9333c841221b

this file was removed from 1.4 as part of
3b6a68b.  as this is a 2.0 only change, restore it there.

Change-Id: Idd7081d9e09b4b725283b4a7965ee37fd169eac8
References: #6842

Fixed a regression in the test suite where the test called
``CompareAndCopyTest::test_all_present`` would fail on some platforms due
to additional testing artifacts being detected. Pull request courtesy Nils
Philippsen.

In some circumstances, ephemeral class objects that are created within
the scope of a test method don't seem to be garbage collected directly
on exit. Filter out classes created in test modules.

Fixes: #7450
Closes: #7451
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/7451
Pull-request-sha: 135a8aaba2c6941460c7f45aa1a55c8f6b9eb43d

Change-Id: I621967bd916089dc1e3f98625fd2a852cd9fd712

Fixed caching-related issue where the use of a loader option of the form
``lazyload(aliased(A).bs).joinedload(B.cs)`` would fail to result in the
joinedload being invoked for runs subsequent to the query being cached, due
to a mismatch for the options / object path applied to the objects loaded
for a query with a lead entity that used ``aliased()``.

Fixes: #7447
Change-Id: I4e9c34654b7d3668cd8878decbd688afe2af5f81

Signed-off-by: Nils Philippsen <nils@tiptoe.de>