From HELP-65363

Currently:

• The dry-run create-with-import call to WiredTiger modifies the table (i.e. sets the dirty flag) because it has to clear the timestamps and write generations stored in the table.
• The dry-run drop-but-keep-the-file call will return EBUSY because the table is dirty. Presumably there is a loop in importCollection or lower that keeps trying that operation until EBUSY is not returned.
• The checkpointer thread runs eventually and cleans the table.
• The next iteration trying to drop the table succeeds and progress is made.

We want to explicitly force a checkpoint before calling drop to avoid waiting on EBUSY until the checkpointer thread creates a checkpoint. This should not evict the collection from the WT metadata because there are no other modifications being made to the collection