The Bechdel Test was designed around the a desire for woman-woman relationships; it explicitly is not about male-female relationships. Adding a gay man to it is like adding a man to lesbian porn. It undermines the very concept.
Let me rephrase my point. The Bechdel Test checks when the stereotypes of male-female relationships dominated over any other kind. You fail the test when the relationship of a woman with anything else depends on a man- it's automatic if there are no other females, and conditional if the two women talk about men. That makes it highly about male-female relationships, even if that is the 'failure' state.
The use of the lesbian porn analogy is interesting, but I think this because of what the Becchdel Test means to you may be much different to what it means to others. The Bechdel Test isn't a test for a lesbian relationship (and no, I'm not saying you are saying it is), but a check that women could be characters without relying on a male-female relationship stereotypes that people held (such that women just talk about men).
The Beccdel test is passed when women can talk to eachother without the gender relationship stereotype coming into play (women focus on men). For people who use this understanding, a gay!Beccdel test would involve the people involved talking without the relationship stereotype coming into play.
Which would not be adding a gay man to the test, but creating a separate test.
Which, for discussion short hand so that people might get a grasp of what is being looked for... could be associated with the Bechdel Test.