Use callable resolver in batch API to allow callbacks in service notation

Tentatively tagging as novice -- it's *reasonably* simple:

1. find places in batch.inc where callbacks are called
2. Use the callable resolver service to get a callable first

My team and i are starting to work on this issue.

Looks good -- all the calls to call_user_func_array() have been changed.

However, this also needs a corresponding docs change.

The docs has been updated .

Change makes sense and searched in batch.inc only for call_user_func_array and all 3 instances have been replaced.

This change makes a lot of sense. A reminder that Drush has its own implementation of batch API (batch.inc) which allows you to harness batch operations when running Drush commands, via drush_backend_batch_process().
It would be very convenient to implement these changes in that file too. I opened an issue in the Drush list and hope to work soon on that patch: https://github.com/drush-ops/drush/issues/5880.
Thanks!

This will need to update \Drupal\Core\Batch\BatchBuilder too so that
\Drupal\Core\Batch\BatchBuilder::setFinishCallback()
\Drupal\Core\Batch\BatchBuilder::addOperation()

Also I think we need test coverage to prove that this actually works... I think there's code in \_batch_next_set() that makes this a bit trickier than the current MR.

We did some modifications in the code according to @alexpott comments. Unfortunately , the pipeline failed and we don't know how to solve it.

$ echo $MODIFIED | tr ' ' '\n' | yarn --cwd=./core run -s spellcheck:core --no-must-find-files --file-list stdin
/scripts-126748-1767911/step_script: line 308: /usr/bin/tr: Argument list too long
/scripts-126748-1767911/step_script: line 308: /usr/bin/yarn: Argument list too long
Cleaning up project directory and file based variables
00:01
ERROR: Job failed: command terminated with exit code 1

Spell checking error fixed by rebasing the MR, pipeline passed (2 stage) Spell checking errors

Some Functional test case fail w.r.rt to batch file change in MR due to which pipeline not able to pass (3 stage), those needs to be addressed

All mentioned changes are addressed in such way that test case failures w.r.t to batch that were previously failing are now passing!!

Please review, moved to NR

There's some logic that could be cleaned up, and some unrelated changes.

Refactored the code logic for improved clarity and cleanliness

Please review , moved NR.

Rebased the MR with latest code, seems fine