TST: remove some Panel/Panel4D deprecation warnings from tests
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=h1) Report
> Merging [#16387](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/16c247bcfb214d296ddf192520db51cb310268e8?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/16387/graphs/tree.svg?src=pr&token=eZ4WkYLtcO&width=650&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #16387      +/-   ##
==========================================
+ Coverage    90.4%    90.4%   +<.01%     
==========================================
  Files         161      161              
  Lines       50975    50977       +2     
==========================================
+ Hits        46083    46088       +5     
+ Misses       4892     4889       -3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.18% <100%> (+0.02%)` | :arrow_up: |
| #single | `40.19% <55.55%> (-0.11%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `80.79% <100%> (+0.03%)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.69% <0%> (-0.1%)` | :arrow_down: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `65.05% <0%> (+1.81%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16387?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/16387?src=pr&el=footer). Last update [16c247b...8f72961](https://codecov.io/gh/pandas-dev/pandas/pull/16387?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/16387?src=pr&el=h1) Report
> Merging [#16387](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/16c247bcfb214d296ddf192520db51cb310268e8?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/16387/graphs/tree.svg?height=150&width=650&token=eZ4WkYLtcO&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #16387      +/-   ##
==========================================
+ Coverage    90.4%    90.4%   +<.01%     
==========================================
  Files         161      161              
  Lines       50975    50977       +2     
==========================================
+ Hits        46083    46088       +5     
+ Misses       4892     4889       -3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.18% <100%> (+0.02%)` | :arrow_up: |
| #single | `40.19% <55.55%> (-0.11%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `80.79% <100%> (+0.03%)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.69% <0%> (-0.1%)` | :arrow_down: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `65.05% <0%> (+1.81%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16387?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/16387?src=pr&el=footer). Last update [16c247b...8f72961](https://codecov.io/gh/pandas-dev/pandas/pull/16387?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
