Add second super:: in non-Windows alternative_locations test

This was needed on both Windows and non-Windows systems ever since
I moved the tests from `tests` to `tests::loc`, but I forgot to
update it for the non-Windows `alternative_locations` test.

Author: EliahKagan

gix-path/src/env/git.rs

@@ -542,7 +542,7 @@ mod tests {
     mod loc {
         #[test]
         fn alternative_locations() {
-            assert!(super::ALTERNATIVE_LOCATIONS.is_empty());
+            assert!(super::super::ALTERNATIVE_LOCATIONS.is_empty());
         }
     }
 }