test-path: move all related test files to a specific directory

To avoid polluting test/

src/test/test-path.c

@@ -258,7 +258,7 @@ int main(int argc, char *argv[]) {
         log_parse_environment();
         log_open();
 
-        assert_se(set_unit_path(TEST_DIR) >= 0);
+        assert_se(set_unit_path(TEST_DIR "/test-path/") >= 0);
 
         for (test = tests; test && *test; test++) {
                 int r;