private boolean computeFallThru() {
		OpTpl[] opVec = pcodeTemplate.getOpVec();
		if (opVec.length <= 0) {
			return true;
		}
		switch (opVec[opVec.length - 1].getOpcode()) {
			case PcodeOp.BRANCH:
			case PcodeOp.BRANCHIND:
			case PcodeOp.RETURN:
				return false;
		}
		return true;
	}
Provide basic form,  restoreXml fills in the rest
@param nm  must provide formal name
@param tp  must provide type
@param sourceName is a description of the source of this payload
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/lang/InjectPayloadSleigh.java