Share blank nodes

[nieqiurong]

In the memory analysis, it was found that there were some blank nodes in mybatis,
Some are line breaks followed by blank strings, which are considered as blank nodes. However, the space occupied by these nodes is meaningless, and it is possible to cache these blank nodes during parsing and only retain one instance

example:

<script>
select * from user
<where>
<if test="1==1">and id = 1</if>
<if test="1==1">and id > 0</if>
</where>
</script>

For example, when parsing the sample script, four line break tags will be created. This is just a simple example, and we will use more dynamic tags in the project.

This modification will not change the original script content.

[coveralls]

coverage: 87.223% (-0.003%) from 87.226%
when pulling e98369d on nieqiurong:202502222213
into a204ffa on mybatis:master.