@Override
	public ReferenceDBManager getReferenceManager() {
		return (ReferenceDBManager) managers[REF_MGR];
	}
Initialize program compiler specification.
During a language upgrade this will provide a temporary spec until setLanguage is complete.
@throws CompilerSpecNotFoundException if the compiler spec cannot be found
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramDB.java