(surviving spouse protections of ERISA do not apply to IRAs, even if funds in the IRA came from an ERISA plan; facts involved decedent who had ERISA plan assets rolled over into IRA and then remarried; IRA beneficiaries were decedent's children who, upon decedent's death claimed entitlement to IRA by reason of beneficiary designation while surviving spouse claimed proceeds via being surviving spouse and that funds came from ERISA plan and were subject to spousal protections; court determined that children entitled to funds).