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):

readline/inputrc/inputrc_test.go

Line 181 in 276299f

return bytes.Split(buf, []byte(delimiter))

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