Method partialCopyShadow

For \b this and another Varnode, establish that either: - bigger = CONCAT(smaller,..) or - smaller = SUBPIECE(bigger) Check through COPY chains and verify that the form of the CONCAT or SUBPIECE matches a given relative offset between the Varnodes. \param op2 is the Varnode to compare to \b this \param relOff is the putative relative byte offset of \b this to \b op2 \return \b true if one Varnode