BUG: Groupby quantiles incorrect bins #33200
Maintain the order of the bins in group_quantile. Updated tests #33200

- [x] closes #33200, closes #33569
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Updated the PR. I did not notice the other PR. It was not referenced in the original issue #33200 . BTW this should also close https://github.com/pandas-dev/pandas/issues/33569 xref #33300 to track.

 @mabelvj This PR seems to be timing out on Windows. is this related to the changes here? @mabelvj Can you merge master? The quantile tests were moved to /tests/groupby/test_quantile.py. thanks @mabelvj for the patch.  Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

```
$ git checkout 1.0.x
$ git pull
```

2. Cherry pick the first parent branch of the this PR on top of the older branch:
```
$ git cherry-pick -m1 2740fb44e5e2ff64087ca7de5999eb30352722f0
```

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

```
$ git commit -am 'Backport PR #33644: BUG: Groupby quantiles incorrect bins #33200'
```

4. Push to a named branch :

```
git push YOURFORK 1.0.x:auto-backport-of-pr-33644-on-1.0.x
```

5. Create a PR against branch 1.0.x, I would have named this PR:

> "Backport PR #33644 on branch 1.0.x"

And apply the correct labels and milestones.

Congratulation you did some good work ! Hopefully your backport PR will be tested by the continuous integration and merged soon!

If these instruction are inaccurate, feel free to [suggest an improvement](https://github.com/MeeseeksBox/MeeseeksDev).
                