Fix index locator cast bool key to float.
- closes #19087

@machenity : Good start!  We're going to need tests and a `whatsnew` entry in `0.24.0`. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22357?src=pr&el=h1) Report
> Merging [#22357](https://codecov.io/gh/pandas-dev/pandas/pull/22357?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/83be235ab8470dc3a4e2fa55c79d54db3abc7e58?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/22357/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/22357?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #22357      +/-   ##
==========================================
+ Coverage   92.05%   92.05%   +<.01%     
==========================================
  Files         169      169              
  Lines       50724    50733       +9     
==========================================
+ Hits        46693    46702       +9     
  Misses       4031     4031
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.46% <100%> (ø)` | :arrow_up: |
| #single | `42.24% <0%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/22357?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/numeric.py](https://codecov.io/gh/pandas-dev/pandas/pull/22357/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9udW1lcmljLnB5) | `97.24% <100%> (ø)` | :arrow_up: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/22357/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.25% <0%> (ø)` | :arrow_up: |
| [pandas/core/dtypes/cast.py](https://codecov.io/gh/pandas-dev/pandas/pull/22357/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2Nhc3QucHk=) | `88.58% <0%> (ø)` | :arrow_up: |
| [pandas/core/internals/blocks.py](https://codecov.io/gh/pandas-dev/pandas/pull/22357/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL2Jsb2Nrcy5weQ==) | `93.84% <0%> (+0.01%)` | :arrow_up: |
| [pandas/core/arrays/integer.py](https://codecov.io/gh/pandas-dev/pandas/pull/22357/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2ludGVnZXIucHk=) | `94.55% <0%> (+0.06%)` | :arrow_up: |
| [pandas/core/dtypes/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/22357/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2Jhc2UucHk=) | `92.68% <0%> (+0.37%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22357?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/22357?src=pr&el=footer). Last update [83be235...dff350a](https://codecov.io/gh/pandas-dev/pandas/pull/22357?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @gfyoung Do your 'tests' mean that i have to write new test case code or just be okay with those codecov test? I believe @gfyoung meant a test for your change. Will you come to the PyCon KR sprint tomorrow?  @scari Yes, i will, but i have a tutorial before that. @gfyoung I added tests and `whatsnew` changes and edit codes with help of @jreback. Thanks. lgtm. small change suggested by @gfyoung  @gfyoung I edited it. Thank you for your suggestion. thanks @machenity 