IssueTracker

R8 has introduced an api that allows setting up feature splits. The api allows for any number of splits to be added, by providing both Providers and a consumer for the splits.
The splits are added through a FeatureSplit.Builder:
https://r8.googlesource.com/r8/+/79854ab890a60f872999585a942bfafa87b19b0c/src/main/java/com/android/tools/r8/R8Command.java#366

This will allow us to:
 1. Have correct behaviour (see https://buganizer.corp.google.com/issues/122902374 for places where the dexsplitter goes south)
 2. Simpler gradle integration, we now only have one call, and no need for intermediates.