Build

All install targets use the "all" target as synchronization point to
prevent race conditions with PGO builds. PGO builds use recursive make,
which can lead to two parallel `./python setup.py build` processes that
step on each others toes.

"test" targets now correctly compile PGO build in a clean repo.
(cherry picked from commit 243ed543)

Co-authored-by: Christian Heimes <christian@python.org>