remove leftover firebird adapter tests.
tyop
sync example and documentation for strong_parameters hash whitelisting.

[ci skip]

This is a follow up to #12609 and integrates #12158.

Thanks @aspiers.
Closes #12158.
Merge pull request #13049 from senny/remove_firebird_tests

remove leftover firebird adapter tests.
changed update counter to act on unscoped model