Fix #8233: write the NUL separator as an escape so the sources stay text

[fskorgen]

Two Java files use a NUL character as a separator, written as a real byte in the source. Git treats those files as binary and skips line-ending normalization, so on Windows a build rewrites them with CRLF and they appear as a ~4200-line change with no content change.

This writes the separator as the escape "\0" instead. Same character at runtime, and both files become normal text files for Git.

Fixes #8233

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