Failed targets acquiring doesn't affect retries

[rihter007]

If TargetsManager fails to acquire targets (which can be a temporary problem), the test will not be retries.

The reason of this problem is that we treat all acquiring errors as fatal and do not retry.
The acquiring errors could be put into the following categories:

• Target manager failed (could be retried)
• Target locking failed (could be a temporary problem if the target is used by someone else)
• Context cancellation + Deadline

All problems except context cancellation that means that the test as cancelled could be retried