[SPARK-3469] Make sure all TaskCompletionListener are called even with failures

This is necessary because we rely on this callback interface to clean resources up. The old behavior would lead to resource leaks.

Note that this also changes the fault semantics of TaskCompletionListener. Previously failures in TaskCompletionListeners would result in the task being reported immediately. With this change, we report the exception at the end, and the reported exception is a TaskCompletionListenerException that contains all the exception messages.
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