Method setOrder

The SeqNum::order field for each PcodeOp must mirror the ordering of that PcodeOp within \b this block. Insertions are usually handled by calculating an appropriate SeqNum::order field for the new PcodeOp, but sometime there isn't enough room between existing ops. This method is then called to recalculate the SeqNum::order field for all PcodeOp objects in \b this block, reestablishing space betw