Fixed Default value list is not correct if contains a null value (T

50040)

Engine will pass a null object if encountered a null value in the
default value list.

engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineTask.java

@@ -1241,10 +1241,7 @@ else if ( result.getClass( ).isArray( ) )
 				{
 					Object value = evaluateExpression( expr, parameter
 							.getDataType( ) );
-					if ( value != null )
-					{
-						results.add( value );
-					}
+					results.add( value );
 				}
 			}
 			return results.toArray( );