Temporarily remove TCP fallback after UDP timeouts

Temporarily remove TCP fallback after UDP timeouts

The retry path in resquery_send() that flipped DNS_FETCHOPT_TCP on a
query whose dispatch had already been bound as UDP in fctx_query() had
no effect on the transport actually used, but did leave a stale TCP
bit visible to downstream consumers (dnstap framing, cookie checks,
the AUTHORITY-NS spoofability guard).

The ineffective code has been removed from resquery_send().  The
TCP fallback functionality will be corrected and restored in the next
commit.

Assisted-by: Claude:claude-opus-4-7
(cherry picked from commit 01523a078a848873be90572171124cdd5c1c7b0c)