test: add function mock debug populate

[machinly]

在 tcl 脚本中增加 populate 方法模拟 redis debug populate 方法，用以填充测试数据。
同时修复 scan 中相关的测试。

[cr-gpt]

The code patch you provided appears to add a new procedure called "populate" for debug purposes. Here are some observations and suggestions for improvement:

1. Error handling: It's generally recommended to handle errors gracefully and provide meaningful error messages to users. Currently, the code uses catch to suppress the error when executing /bin/kill -9. Consider adding appropriate error handling or logging in case of any failures.

2. Magic numbers: The value "-9" in the exec command is a magic number, which might make the code less readable and maintainable. Consider using a named constant or explaining the purpose of this value with a comment.

3. Code formatting: Ensure consistent code formatting throughout the codebase. Inconsistent indentation can make the code harder to read and maintain. Make sure to use a consistent number of spaces or tabs for indentation.

4. Variable naming: Consider choosing more descriptive names for variables. For example, instead of using counter, you could use a name that reflects its purpose, such as iteration.

5. Readability: Enclose expressions involving assignment, increment, and condition checks within parentheses to improve readability. For example, in the populate procedure, the expression $counter < $size would be clearer if written as ($counter < $size).

6. Use of quotes: Verify whether the current quotation style ("key:$counter") is appropriate for the application context. Depending on the requirements, it may be necessary to use single quotes or escape special characters within the string.

7. Documentation: Consider adding comments or docstrings to explain the purpose and functionality of the procedures, especially for the newly added populate procedure.

Remember that without having the complete code and context, it's difficult to assess all potential bug risks or suggest further improvements. It's essential to thoroughly test the code after making any changes to ensure its correctness and performance.

[Mixficsol]

下面这个注释需要保留吗