TST: solve test failure on 32bit systems
- [x] closes #22813
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

#22296 introduced a test, where ``dtype=np.int64`` was used, but ``np.intp`` is needed for the test to pass on 32bit systems also. This fixes that.

After this PR, the pandas test suite passes with no failures on my 32bit python installation on Windows 10.

Hello @topper-123! Thanks for submitting the PR.

 - There are no PEP8 issues in the file [`pandas/tests/indexes/test_base.py`](https://github.com/topper-123/pandas/blob/de744603d359b00022c31b93e8d115744f347693/pandas/tests/indexes/test_base.py) !

 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22908?src=pr&el=h1) Report
> Merging [#22908](https://codecov.io/gh/pandas-dev/pandas/pull/22908?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/f4fae353eaaa719db335ec2b21259932de30f46d?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/22908/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/22908?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #22908   +/-   ##
=======================================
  Coverage   92.18%   92.18%           
=======================================
  Files         169      169           
  Lines       50830    50830           
=======================================
  Hits        46860    46860           
  Misses       3970     3970
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.6% <ø> (ø)` | :arrow_up: |
| #single | `42.37% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22908?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/22908?src=pr&el=footer). Last update [f4fae35...de74460](https://codecov.io/gh/pandas-dev/pandas/pull/22908?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 looks fine, but let's fix #22924 first thanks!