test: properly order test assertion variables

PR-URL: #23503
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

test/parallel/test-child-process-set-blocking.js

@@ -31,5 +31,5 @@ const cp = ch.spawn('python', ['-c', `print ${SIZE} * "C"`], {
 });
 
 cp.on('exit', common.mustCall(function(code) {
-  assert.strictEqual(0, code);
+  assert.strictEqual(code, 0);
 }));