For purposes of determining whether a trust that is subject to the rule against perpetuities violates said rule, if there is only one beneficiary of the trust who is entitled or eligible to receive distributions of income or principal from the trust, such beneficiary holds a general power of appointment over the trust, and no other person has a power to appoint any part of the trust to anyone other than the beneficiary, then the beneficiary has a vested interest in the trust, regardless of whether such general power is presently exercisable or is exercisable only at the powerholder’s death.