StorageToAoMigrationUpgradeTask takes a long time

It's been observed that when upgrading past 5.4.4, the StorageToAoMigration upgrade task can take a long time. In at least one instance, it was observed that a single page with many versions (~500) and many tasks (~250) was holding up the task.

This hasn't been replicated, but I'm raising this bug report as a placeholder in case others run into the same issue so we can consolidate the investigation here.

What we know:

• Multiple users have seen similar symptoms.
• It seems to consistently take about 2.5 seconds to migrate each task