Method cancelExtensions

\brief Eliminate input extensions on given binary PcodeOp Make some basic checks. Replace the input and output Varnodes with smaller sizes. \param longform is the given binary PcodeOp to modify \param subOp is the PcodeOp truncating the output of \b longform \param ext0In is the first input Varnode before the extension \param ext1In is the second input Varnode before the extension \param data is