Update code.php

[oceanwap]

I have:

• Read the project README, including the benchmark descriptions
• Read the PR template instructions before I deleted them
• Understood that if I have changed something that could impact performance of one or more contributions, I should provide results benchmark runs, using the run.sh script, from before and after the change.

Description of changes

PHP JIT doesn't work so well for global code, wrapping it in a function makes JIT work better and code faster.
Also in a real word project a code would be wrapped in a class or function, so it's more realistic scenario.

[oceanwap]

@bddicken Please review the PR

[jszczypk]

I have got almost 40% shorter time with JIT by wrapping the code in function.

[oceanwap]

@bddicken
I am not sure who will merge it, can someone mere it?