Please use FileSystem tools to finish the following task:

### Task Description

You need to split a large text file into multiple smaller files with equal character counts. The task involves creating a new directory and splitting the content into exactly 10 files.

### Task Objectives

1. **Create a new directory** named `split` in the test directory
2. **Split the file** `large_file.txt` into exactly 10 files with equal character counts
3. **Name the files** as `split_01.txt`, `split_02.txt`, ..., `split_10.txt` in the `split` directory
