xdge: drop redundant test_paths.ml duplicate (E610)
test_paths.ml redefined test_v and test_config_file_missing — both
already covered by test_xdge.ml's test_v and test_config_file_not_found
with the same assertions. Removing the file (and its dune entry, the
test.ml suite reference) since the coverage is preserved by test_xdge.