Except to the extent otherwise provided in the governing instrument of a statutory trust or in this subchapter, the laws of this State pertaining to trusts are hereby made applicable to statutory trusts; provided however, that for purposes of any tax imposed by this State or any instrumentality, agency or political subdivision of this State a statutory trust shall be classified as a corporation, an association, a partnership, a trust or otherwise, as shall be determined under the United States Internal Revenue Code of 1986 [26 U.S. Code § 1 et seq.], as amended, or under any successor provision.