test: fix printf("%s", NULL) in error path ../test/common.c: In function ‘test_get_path’: ../test/common.c:171:9: warning: ‘%s’ directive argument is null [-Wformat-overflow=] 171 | fprintf(stderr, "Failed to allocate path (%d chars) for %s\n", | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 172 | (int) path_len, path); | ~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Ran Benita <ran@unusedvar.com>