Handle exceptions when AsyncLocalizer tries to get local resources

Supervisor relies on AsyncLocalizer to download blobs from blob store.
AsyncLocalizer uses downloadService pool to process CompletableFuture objects in parallel.

We have noticed a case that while the downloading task is waiting for a thread to execute, new assignment changes will try to release the slot by dereferences all of the related local resources.

However, reading local resources assumes two base blob downloading task have been completed which is not always true.