Remove unhittable methods in internals
And one more 24024 in test cleanup
lgtm. some lint issues. ping on green. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24594?src=pr&el=h1) Report
> Merging [#24594](https://codecov.io/gh/pandas-dev/pandas/pull/24594?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/479ddcb63131ed48862c2ebffb8a94411f389d83?src=pr&el=desc) will **increase** coverage by `0.02%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24594/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24594?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24594      +/-   ##
==========================================
+ Coverage   92.36%   92.38%   +0.02%     
==========================================
  Files         166      166              
  Lines       52497    52478      -19     
==========================================
- Hits        48490    48483       -7     
+ Misses       4007     3995      -12
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.81% <100%> (+0.01%)` | :arrow_up: |
| #single | `43.04% <0%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24594?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/internals/blocks.py](https://codecov.io/gh/pandas-dev/pandas/pull/24594/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL2Jsb2Nrcy5weQ==) | `94.49% <100%> (+0.7%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24594?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/24594?src=pr&el=footer). Last update [479ddcb...c8b3323](https://codecov.io/gh/pandas-dev/pandas/pull/24594?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/24594?src=pr&el=h1) Report
> Merging [#24594](https://codecov.io/gh/pandas-dev/pandas/pull/24594?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/479ddcb63131ed48862c2ebffb8a94411f389d83?src=pr&el=desc) will **increase** coverage by `0.02%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24594/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24594?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24594      +/-   ##
==========================================
+ Coverage   92.36%   92.38%   +0.02%     
==========================================
  Files         166      166              
  Lines       52497    52478      -19     
==========================================
- Hits        48490    48483       -7     
+ Misses       4007     3995      -12
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.81% <100%> (+0.01%)` | :arrow_up: |
| #single | `43.04% <0%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24594?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/internals/blocks.py](https://codecov.io/gh/pandas-dev/pandas/pull/24594/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL2Jsb2Nrcy5weQ==) | `94.49% <100%> (+0.7%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24594?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/24594?src=pr&el=footer). Last update [479ddcb...c0b544e](https://codecov.io/gh/pandas-dev/pandas/pull/24594?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 ping thanks!