fix:修复CWSEvaluator比较切分语句时的计算错误

Description

CWSEvaluator类中的compare方法比较标准答案与分词结果时，循环逐一比较词语时，predLen的计算存在错误，增加了另一个数组的对应index位置词语的长度，而不是predArray本身数组的

Type of Change

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• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

运行CWSEvaluatorTest的testGetPRF()方法debug即可

Checklist

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• ⚠️Changes must be made on dev branch instead of master
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have checked my code and corrected any misspellings