void setConflictDecision(int decision) {
		if (decision == ASK_USER || decision == KEEP_LATEST || decision == KEEP_MY) {
			conflictOption = decision;
		}
		else {
			throw new IllegalArgumentException();
		}
	}
For JUnit testing only, set the option for resolving a conflict.
@param decision ASK_USER, PICK_LATEST, PICK_MY
Ghidra/Features/Base/src/main/java/ghidra/app/merge/listing/RegisterMergeManager.java