Consider making PGO the default build of python-build-standalone

Linux From Scratch has made PGO the default for Python since version [11.0](https://www.linuxfromscratch.org/lfs/view/11.0/chapter08/Python.html). All other distros besides Gentoo enable PGO (Profile Guided Optimization) by default when building Python. GCC and Clang both support compiling programs with PGO.

So it's a good idea to see if we can approve to make PGO the default build of the python-build-standalone project.

No files or tests are named. Start by locating the build configuration and existing PGO handling, then compare the Linux From Scratch and other distribution defaults cited in the issue. Done means deciding whether PGO should be enabled by default across supported builds and documenting or testing the resulting build behavior.

Written by the indexing model from the issue text.