- Raise passing 'score' from 50% to 90% to filter out very incomplete
merge operations.
- Catch unfit sections passing the match test; possible for blit_dst
data but will likely be always harmless. Disabled in release builds by default.

- Attempt to identify blit operations that will be flushed immediately
after and just do them on CPU instead if the transformation is trivial.
- If only a single blit section is contributing to an atlas merge op, the
threshold should be 100%. The only acceptable result here is a
truncation.

…extures to avoid needless barriers

- There still does not exist a ranged flush implementation which is required.
- TODO: Implement this properly

- Avoids WCB requirement for now to keep res scaling working correctly.
- TODO: Fix this properly