Repeated optimizations in tier 2, due to the optimizer "failing" when it cannot optimize perfectly.

[markshannon]

The tier 2 optimizer fails whenever it cannot optimize the entire trace, which results in a large number of repeated attempts to optimize the same code.

While we should add some form of backoff #116968 to mitigate this, we should also fix the root cause.
If the optimizer can only optimize up to some point in the code, it should not throw away the work it has done.

Linked PRs

• GH-117066: Tier 2 optimizer: Don't throw away good traces if we can't optimize them perfectly. #117067