I first attempted to extract logic from the code that normalizes DNs, but I was unsuccessful. This is a hack but it works.

Since that behavior changed, and is now under the malformed DN context.

Especially from the last attribute value.

Disabling some for now since this is based on `Net::LDAP::DN`.

for normalizing and parsing DNs

…to stop copy pasting test cases.

Fix LDAP config key name

See merge request gitlab-org/gitlab-ce!14739