Merge 5.4 into 5.x

[mongodb-php-bot]

Merge new changes from 5.4 into 5.x.

Commits

• Remove usage of deprecated getMongoDB method (Remove usage of deprecated getMongoDB method in tests #3367): d56aefa
• Replaced a too strict assertion in DatabaseSessionHandler that prevented to use the sessions at all with a more simple sanity check ([5.x] Replaced a too strict assertion in DatabaseSessionHandler.php that prevented to use the sessions at all with a more simple sanity check. Test already failed on that, now they pass. #3366) (PHPORM-327 Fix invalid assert in DatabaseSessionHandler::read() #3368): 5a78951

Resolving conflicts

To resolve any conflicts, check out the temporary branch and run the following command:

git merge 5.x

Ignoring changes

To ignore from the remote branch, first reset the temporary branch to 5.x and manually merge using the `ours` merge strategy:

git reset --hard 5.x
git merge --strategy=ours 5.4

Then, push the temporary branch to upate the pull request.