(petitioner claimed head-of-household status and dependency deduction for a person she claimed was her son that was only two years younger than petitioner; petitioner’s testimony not credible that claimed son was adopted and no other family relationship existed; alleged son not member of petitioner’s household during tax year in issue, but only lived with petitioner temporarily during tax year; “son” too old to be qualifying child and lack of evidence that “son” disabled; lack of evidence that petitioner provided more than 50 percent of support to “son”).