Make test-cargo CI run on Windows

[sffc]

When run on Windows, I get errors such as

cp -p "D:\a\icu4x\icu4x\docs\tutorials\cargo_tests/target"/release/demo_buffer bin/demo_buffer
./bin/icu4x-datagen \
	--format blob \
	--keys-for-bin bin/demo_buffer \
	--locales my en-ZA \
	--cldr-tag latest \
	--overwrite \
	--out buffer_data.postcard
Error: bin/demo_buffer

Caused by:
    The system cannot find the file specified. (os error 2)

Need to debug. Probably easy to do locally; just get cargo make test-cargo-tutorial-local to succeed.

When ready, enable windows in build-test.yml

[hiralkhatik123]

may be The system cannot find the file specified. the file path is incorrect. Verify the file's path.