[php-src] Issue #8619: Relocate JIT buffer close to PHP and achieve 2% more performance

Issue: https://github.com/php/php-src/issues/8619 Author: stkeke ### Description This is a JIT buffer relocation experiment inspired by this blog https://v8.dev/blog/short-builtin-calls > For 64-bit applications, branch prediction performance can be negatively impacted when the target of a branch is more than 4 GB away from the branch. We set up a big 500MB char array which is close to PHP .text segment and use it as our own JIT buffer (originally allocated by opcache.so and was close to opcache in virtual address). In our benchmark, we found PHP interpreter achieved 2% performance and much better branching performance. Hopefully, you community experts can advise a more elegant and robust method to implement this performance optimization. Here is what did a super simple experiment and the reference patch: https://github.com/php/php-src/pull/8618