Remove unused private fields in tests

Author: hazendaz

src/test/java/org/apache/ibatis/builder/CustomObjectWrapperFactory.java

@@ -21,8 +21,6 @@
 
 public class CustomObjectWrapperFactory implements ObjectWrapperFactory {
 
-  private String option;
-
   @Override
   public boolean hasWrapperFor(Object object) {
     return false;

src/test/java/org/apache/ibatis/domain/misc/RichType.java

@@ -24,8 +24,6 @@ public class RichType {
 
   private RichType richType;
 
-  private String richField;
-
   private String richProperty;
 
   private Map richMap = new HashMap<>();

src/test/java/org/apache/ibatis/reflection/typeparam/Calculator.java

@@ -18,8 +18,6 @@
 public class Calculator<T> {
   protected T id;
 
-  private T fld;
-
   protected T attribute;
 
   public T getId() {