Eng 5616 determinism

Eliminate unused determinism flags in cached "Core" plans.
Do more determinism checking at the statement level rather than at the plan (node) level.
Do most "content determinism" checks by separate "order determinism" and "has limit or offset" checks.
Absorb the fragmentize function into QueryPlanner for simplicity.
Eliminate "scan rewrites for determinism" in collector fragments that slowed the plans but could not guarantee determinism.