[IMP] account: Clean common tests classes

addons/account/tests/__init__.py

addons/account/tests/account_minimal_test.py

addons/account/tests/account_test_classes.py

addons/account/tests/account_test_no_chart.py

addons/account/tests/account_test_savepoint.py

addons/account/tests/account_test_users.py

addons/account/tests/common.py

addons/account/tests/invoice_test_common.py

addons/account/tests/test_account_bank_statement.py

addons/account/tests/test_account_fiscal_year.py

addons/account/tests/test_account_invoice_report.py

addons/account/tests/test_account_journal_dashboard.py

addons/account/tests/test_account_move_entry.py

addons/account/tests/test_account_move_in_invoice.py

addons/account/tests/test_account_move_in_refund.py

addons/account/tests/test_account_move_out_invoice.py

addons/account/tests/test_account_move_out_refund.py

addons/account/tests/test_account_move_rounding.py

addons/account/tests/test_bank_statement_reconciliation.py

addons/account/tests/test_control_journal_account.py