test: fs_fchmod_archive_readonly must return a value

PR-URL: https://github.com/libuv/libuv/pull/1843
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

test/test-fs.c

@@ -3361,5 +3361,7 @@ TEST_IMPL(fs_fchmod_archive_readolny) {
     /* Restore Archive flag for rest of the tests */
     r = SetFileAttributes("test_file", FILE_ATTRIBUTE_ARCHIVE);
     ASSERT(r != 0);
+
+    return 0;
 }
 #endif