wrapper 支持 clear

mybatis-plus-core/src/main/java/com/baomidou/mybatisplus/core/conditions/AbstractLambdaWrapper.java

@@ -97,11 +97,4 @@ public abstract class AbstractLambdaWrapper<T, Children extends AbstractLambdaWr
             columnMap = LambdaUtils.getColumnMap(entityClass);
         }
     }
-
-    @Override
-    public void clear() {
-        super.clear();
-        initColumnMap = false;
-        columnMap = null;
-    }
 }

mybatis-plus-core/src/main/java/com/baomidou/mybatisplus/core/conditions/AbstractWrapper.java

@@ -444,7 +444,6 @@ public abstract class AbstractWrapper<T, R, Children extends AbstractWrapper<T,
     @Override
     public void clear() {
         entity = null;
-        entityClass = null;
         paramNameSeq.set(0);
         paramNameValuePairs.clear();
         expression.clear();