(Copied from Internal Issue 309101832.)

Classes should be dex'd by either the dexing task or the dexing transform, not both.

This was always the intent, but we may have changed this behavior by accident during a refactoring (AGP 8.0).

Size of the regression (DexArchiveBuilderTask and TOTAL_BUILD_TIME):

Base100:
- Base100_Java8_buildscriptUpdate: 8.3s -> 15.3s; 199s -> 220s
- Base100_Java8_cleanBuild: 3.1s -> 4.5s; 47s -> 49s
- Base100_Java8_codeImplChange: 19ms -> 226ms; Not noticeable
SantaTracker:
- SantaTracker_cleanBuild: 0.8s -> 1s; Not noticeable
- SantaTracker_codeImplChange: 13ms -> 597ms; ~5.5s -> 6s

Other benchmarks either don't have regressions (probably due to their project structures) or have similar regressions.