BUG: support pandas objects in iloc with old numpy versions
 - [x] closes #17193
 - [x] tests added / passed
 - [x] passes ``git diff master -u -- "*.py" | flake8 --diff``
 - [x] whatsnew entry

@toobaz : I'm not sure if you saw my comment, but we intend to drop support for `numpy` < 1.9 in this upcoming release per #17002. > @toobaz : I'm not sure if you saw my comment, but we intend to drop support for numpy < 1.9 in this upcoming release per #17002.

Yes, sorry, I saw it now only. Shall I rebase just leaving the new test? It makes sense regardless of numpy versions. @toobaz : No worries!  I'm a little hesitant to accept your "patch" (i.e. the change in the non-test file) if it's not necessary for newer versions of `numpy`.  However, I think we would be perfectly fine just accepting the test (though we wouldn't merge until after #17002). > However, I think we would be perfectly fine just accepting the test (though we wouldn't merge until after #17002).

Sure, that's what I meant: I will then wait for #17002 (or at least for the numpy version used in circleci to change) and then rebase leaving the test only. Ah, okay.  We're on the same page here.  Absolutely. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=h1) Report
> Merging [#17194](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/3c833db29b6f5977c78d1ade791a09a5b29cedb8?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17194/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17194      +/-   ##
==========================================
- Coverage   91.01%   90.99%   -0.02%     
==========================================
  Files         162      162              
  Lines       49502    49503       +1     
==========================================
- Hits        45053    45045       -8     
- Misses       4449     4458       +9
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.77% <100%> (ø)` | :arrow_up: |
| #single | `40.27% <100%> (-0.06%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/internals.py](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzLnB5) | `94.24% <100%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.71% <0%> (-0.1%)` | :arrow_down: |
| [pandas/conftest.py](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree#diff-cGFuZGFzL2NvbmZ0ZXN0LnB5) | `96.77% <0%> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=footer). Last update [3c833db...4d21861](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=h1) Report
> Merging [#17194](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/3c833db29b6f5977c78d1ade791a09a5b29cedb8?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17194/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17194      +/-   ##
==========================================
- Coverage   91.01%   90.99%   -0.02%     
==========================================
  Files         162      162              
  Lines       49502    49504       +2     
==========================================
- Hits        45053    45045       -8     
- Misses       4449     4459      +10
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.77% <100%> (-0.01%)` | :arrow_down: |
| #single | `40.27% <100%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/internals.py](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzLnB5) | `94.21% <100%> (-0.04%)` | :arrow_down: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.71% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=footer). Last update [3c833db...b0a4b6b](https://codecov.io/gh/pandas-dev/pandas/pull/17194?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 > you can be explcit and use _np_version_under1p19 (then this is easier to remove later).

done

> alternatively the np.asarray may work.

Unfortunately fails when ``indexer`` is a slice thanks @toobaz 