lib/path/tests: Fix property tests when "-n" is generated

When "-n" is generated by the property tests, it causes `echo` to not
output the string since it's interpreted as an option. Apparently
there's no good way to print "-n" with `echo` [1], so switching to
`printf` instead

[1]: https://unix.stackexchange.com/questions/85846/how-can-i-print-n-with-echo

lib/path/tests/prop.sh

@@ -55,7 +55,7 @@ fi
 declare -a strings=()
 mkdir -p "$tmp/strings"
 while IFS= read -r -d $'\0' str; do
-    echo -n "$str" > "$tmp/strings/${#strings[@]}"
+    printf "%s" "$str" > "$tmp/strings/${#strings[@]}"
     strings+=("$str")
 done < <(awk \
     -f "$SCRIPT_DIR"/generate.awk \