Deleting SqlNodeBase and its subclasses

I took a look again, but these tests are not useful, I'm afraid.
To test these classes' functionality, see DynamicSqlSourceTest.
https://github.com/mybatis/mybatis-3/blob/8ac3920afd669f1ae54e21a2d00aa88416f9c29a/src/test/java/org/apache/ibatis/builder/xml/dynamic/DynamicSqlSourceTest.java

Author: harawata