Major Description
We're currently using `totalCoresAcquired` to account for registered resources, which is incorrect. That variable measures the number of cores the scheduler has accepted. We should be using `totalCoreCount` like the other schedulers do.
Fixing this is important for locality, since users often want to wait for all executors to come up before scheduling tasks to ensure they get a node-local placement.
original PR to add support: https://github.com/apache/spark/pull/8672/files
