private void updateMapping(DataType prevDT, DataType newDT) {
		DWARFDataType byPrevDT = dataTypeInstanceToDDTMap.get(prevDT);
		if (byPrevDT != null) {
			dataTypeInstanceToDDTMap.put(newDT, byPrevDT);
			byPrevDT.dataType = newDT;
		}
	}
Returns true if the previously imported data type should be reused.
<p>
Don't re-use empty structs (isNotYetDefined) to ensure that newer
definitions of the same struct are given a chance to be resolved() 
into the DTM. 

@param alreadyImportedDT dataType to check
@return boolean true if its okay to reuse the data type
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf/DWARFDataTypeImporter.java