移除升级遗留代码.

https://github.com/baomidou/mybatis-plus/issues/6370

mybatis-plus-extension/src/main/java/com/baomidou/mybatisplus/extension/plugins/inner/TenantLineInnerInterceptor.java

@@ -21,7 +21,6 @@ import com.baomidou.mybatisplus.extension.plugins.handler.TenantLineHandler;
 import com.baomidou.mybatisplus.extension.toolkit.PropertyMapper;
 import lombok.*;
 import net.sf.jsqlparser.expression.Expression;
-import net.sf.jsqlparser.expression.StringValue;
 import net.sf.jsqlparser.expression.operators.relational.EqualsTo;
 import net.sf.jsqlparser.expression.operators.relational.ExpressionList;
 import net.sf.jsqlparser.expression.operators.relational.ParenthesedExpressionList;
@@ -113,9 +112,6 @@ public class TenantLineInnerInterceptor extends BaseMultiTableInnerInterceptor i
         // fixed gitee pulls/141 duplicate update
         List<UpdateSet> duplicateUpdateColumns = insert.getDuplicateUpdateSets();
         if (CollectionUtils.isNotEmpty(duplicateUpdateColumns)) {
-            EqualsTo equalsTo = new EqualsTo();
-            equalsTo.setLeftExpression(new StringValue(tenantIdColumn));
-            equalsTo.setRightExpression(tenantId);
             duplicateUpdateColumns.add(new UpdateSet(new Column(tenantIdColumn), tenantId));
         }