(decedent's revocable trust funded a marital trust and credit shelter trust via fractional formula clause with no asset allocated to marital trust; Form 706, by error, included property funding credit shelter trust on Schedule M for which QTIP election made; later, different legal counsel discovered error and requested ruling on matter; IRS noted that Rev. Proc. 2001-38 treats as void any QTIP election to extent not necessary to reduce estate tax liability to zero; QTIP election, therefore, disregarded and assets of credit shelter trust not included in estate of surviving spouse; surviving spouse also not treated as transferor of assets in credit shelter trust for GSST purposes).