\brief Check for p-code that is deemed illegal for a \e snippet This method facilitates enforcement of the formal rules for snippet code. - Branches must use p-code relative addressing. - Snippets can only read/write from temporary registers - Snippets cannot use BRANCHIND, CALL, CALLIND, CALLOTHER, STORE, SEGMENTOP, CPOOLREF, NEW, MULTIEQUAL, or INDIRECT \return \b true if the current snippet i