Describe the bug
convertToPinyinList方法，返回了所有同音字的拼音。

Code to reproduce the issue
Provide a reproducible test case that is the bare minimum necessary to generate the problem.

System.out.println(HanLP.convertToPinyinString("你好", " ", false));
// ni hao hao

Describe the current behavior
convertToPinyinList方法返回了多音字所有的拼音，导致返回的拼音字符串有多余的多音字，同时当需要转拼音字符串有中英混杂时，会出现报错IndexOutOfBoundaryException。1.7.8无此问题。

Expected behavior
“你好”返回“ni hao”而不是“ni hao hao”。

System information

• Linux、Windows
• Python version:
• HanLP version:1.8.0

Other info / logs
Include any logs or source code that would be helpful to diagnose the problem. If including tracebacks, please include the full traceback. Large logs and files should be attached.

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