Evaluate Profile-Guided Optimization (PGO)

Hi!

Recently I checked Profile-Guided Optimization (PGO) improvements on multiple projects. The results are [here](https://github.com/zamazan4ik/awesome-pgo/).

Since PGO showed measurable improvements in compiler/interpreter-like workloads (V8, CPython, Clang, Clangd, clang-format, GCC, Rustc, etc.) I think it could be useful to check PGO for Hashlink too.

We need to perform PGO benchmarks on the project. And if it shows improvements - add a note about possible improvements in Hashlink performance with PGO. Providing an easier way (e.g. a build option) to build scripts with PGO can be useful for the end-users too.