[bug-66433] Boolean functions should blank cells. Thanks to Patrick Böker

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1906836 13f79535-47bb-0310-9956-ffa450edef68

poi/src/main/java/org/apache/poi/ss/formula/functions/BooleanFunction.java

@@ -18,6 +18,7 @@
 package org.apache.poi.ss.formula.functions;
 
 import org.apache.poi.ss.formula.TwoDEval;
+import org.apache.poi.ss.formula.eval.BlankEval;
 import org.apache.poi.ss.formula.eval.BoolEval;
 import org.apache.poi.ss.formula.eval.ErrorEval;
 import org.apache.poi.ss.formula.eval.EvaluationException;
@@ -91,7 +92,7 @@ public abstract class BooleanFunction implements Function,ArrayFunction {
                 continue;
             }
 
-            if (arg == MissingArgEval.instance) {
+            if (arg == MissingArgEval.instance || arg == BlankEval.instance) {
                 tempVe = false;     // missing parameters are treated as FALSE
             } else {
                 tempVe = OperandResolver.coerceValueToBoolean(arg, false);