python3: use regrtest instead of PyBench for profile-guided-optimisation
PyBench takes a long time to run, also upstream have removed it from Python and
instead use test.regrtest —pgo to profile the interpreter.
The results are good: not only does Python compile faster (~300s vs ~600s on my
machine) but Phoronix’s PyBench test runs in 2130ms compared to 2229ms when
using PyBench to train (and 2345ms with PGO disabled).
Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
