Task failed on bulk argument failure

[aahovhannisyan]

When one of the bulk arguments of a task is failed, the task status is set to failed also, and the rest of the registered bulk arguments are ignored and not processed.
In order to resolve this issue, I think we must process failed tasks (having registered bulk arguments) also or set bulk argument status to succeeded in all cases.

[arsendovlatyan]

I think we need to have new status, in the middle of succeeded and failed, so, we can mark this as finished, but not successfully. @zzhovo what do you think ?

[zzhovo]

When one of the bulk arguments of a task is failed, the task status is set to failed also.
I can't agree with this statement.
Here are the cases the task is set as failed without processing all the remaining arguments:

1. The task is set to be failed as default, so if the task callback doesn't change it to be succeeded the entire task will fail. This is done to prevent processing all the bulk arguments when there's a technical issue, for example the callback doesn't exist, or the callback throws runtime error.
2. The callback may decide not to process the remaining bulk arguments any more and doesn't change the task run status to be succeeded. For example there can be some time sensitive cases, like find_something_good callback doesn't want to process all the remaining bulk arguments when it got something good, or say a lazy_translate callback decides not to translate its bulk arguments for a certain language anymore.

In the case the callback confirms that the task is not failed but succeeded, then that task will be in progress if it still have bulk arguments to process.

[zzhovo]

In the case we don't want those 2 cases above to exist, then this commit
8553418
can be merged immediately. Just remove the code instead of commenting it.

[arsendovlatyan]

The 2 cases described above make sense to me, however, by now never faced them, instead, we have lot of cases, where task fails instead of going forward to next arguments.

Ideally, this can be a general config or per-task parameter, but let's keep it simple for now and remove the code as @zzhovo suggested. @eriktad please update the PR.