Where accumulations of surplus income are made during a minority under any statutory power or under the general law, the period for which such accumulations are made is not (whether the trust was created or the accumulations were made before or after the commencement of this Act) to be taken into account in determining the periods for which accumulations are permitted to be made by the last preceding section, and accordingly an express trust for accumulation for any other permitted period shall not be deemed to have been invalidated or become invalid, by reason of accumulations also having been made as aforesaid during such minority.