Method linkSymbolReference

A reference to a symbol (i.e. &varname) is typically stored as a PTRSUB operation, where the first input Varnode is a \e spacebase Varnode indicating whether the symbol is on the \e stack or at a \e global RAM location. The second input Varnode is a constant encoding the address of the symbol. This method takes this constant Varnode, recovers the symbol it is referring to, and stores on the HighV