Fix Windows tests for `.inputrc` code

[maxlandon]

There is a weird bug with Github actions running tests for inputrc package on Windows: The testdata files are read correctly, but split accordingly to their delimiters. The tests therefore fail.

Example workflow failure: https://github.com/reeflective/readline/actions/runs/4904982567/jobs/8758471276

Function failing (bytes.Split has everything it needs but does not do its job): https://github.com/reeflective/readline/blob/276299f842183d9f68bde3a1fbe726e009c1e672/inputrc/inputrc_test.go#L181

The tests however work correctly when run locally on a Windows machine.