The answer should definitely not be deleted. Consider that all clarifications to questions (and answers for that matter, but here we are discussing a question) are supposed to be edited into the question itself. Comments are ephemeral by design, and can be deleted by a moderator at any time without any notice. Any clarifications made to a post in a comment do not exist in the official record. So we certainly shouldn't be deleting an answer based on a clarification that doesn't even exist.
Now let's suppose that the clarification in the comment was actually edited into the question. Then it would simply be a case of a question that was changed after an answer had already been posted, for which we already have the following authoritative answer:
Once a question has an answer that is considered valuable by either
the community (through upvotes) or the asker (through acceptance), no
one, including the asker, ought to edit the question in a way that
changes its meaning sufficiently to invalidate the existing answer. If
people want to get answers to a different question, they should ask
that question separately.
Otherwise, the edit invalidates valuable content and/or requires more
work from answerers or the community to update the answers to keep up
with the updated question.
In cases where a question is ambiguous, such that there are multiple
possible interpretations of what it is asking for, it should be closed
until it's edited to be sufficiently precise. The earlier this happens
in the question's life-cycle, the better. If the asker notices that
there are answers that either don't address the asker's intent or
assume multiple interpretations of that intent, the asker should edit
the question as soon as possible to be more precise and should comment
to the answerers accordingly.
So once again there would be no reason to delete the answer.
However, I don't think there would be anything wrong with an answerer adding to his answer out of the goodness of his heart to address a later clarification, but it should certainly not be required, and the clarification should not be included in the question.
If the questioner sincerely desires an answer to their clarified question, they can simply ask a new one and link to the first one if it provides relevant context.