relay: Fix memory leak on BUG() code path

Introduced in bf10206e9e which is not
released yet thus no changes file.

Found by Coverity with cid #1495786.

Fixes #40532

Signed-off-by: David Goulet <dgoulet@torproject.org>

src/feature/relay/selftest.c

@@ -256,6 +256,7 @@ router_do_orport_reachability_checks(const routerinfo_t *me,
     const tor_addr_port_t *ap = extend_info_get_orport(ei, family);
     if (BUG(!ap)) {
       /* Not much we can do here to recover apart from screaming loudly. */
+      extend_info_free(ei);
       return;
     }
     log_info(LD_CIRC, "Testing %s of my %s ORPort: %s.",