Enhance PAL initialization order (#34308)

Enhance PAL initialization order (#34308)

* Enhance PAL initialization order

The CGroups initialization has _ASSERTE that is not asserting because
debugging support was being initialized after the CGroups initialization.

This change moves the debugging support initialization to the earliest
possible point. It also modifies it so that it doesn't depend on the
PAL env functions and uses getenv instead. And finally, initialization
of the critical section for debug printf is moved to the very end
of DBG_init_channels just as a little cleanup.