Revert changes to test regexes
- [X] maybe closes #25867


Reverted to state before #25752 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25874?src=pr&el=h1) Report
> Merging [#25874](https://codecov.io/gh/pandas-dev/pandas/pull/25874?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/51c6a05477ffb5835ee52fc0bbb26e2f64f13bf7?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/25874/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25874?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #25874   +/-   ##
=======================================
  Coverage   91.48%   91.48%           
=======================================
  Files         175      175           
  Lines       52881    52881           
=======================================
  Hits        48376    48376           
  Misses       4505     4505
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.04% <ø> (ø)` | :arrow_up: |
| #single | `41.83% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25874?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/25874?src=pr&el=footer). Last update [51c6a05...097a67f](https://codecov.io/gh/pandas-dev/pandas/pull/25874?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/25874?src=pr&el=h1) Report
> Merging [#25874](https://codecov.io/gh/pandas-dev/pandas/pull/25874?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/51c6a05477ffb5835ee52fc0bbb26e2f64f13bf7?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/25874/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25874?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #25874   +/-   ##
=======================================
  Coverage   91.48%   91.48%           
=======================================
  Files         175      175           
  Lines       52881    52881           
=======================================
  Hits        48376    48376           
  Misses       4505     4505
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.04% <ø> (ø)` | :arrow_up: |
| #single | `41.83% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25874?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/25874?src=pr&el=footer). Last update [51c6a05...097a67f](https://codecov.io/gh/pandas-dev/pandas/pull/25874?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @h-vetinari yeah not really sure why this fails the wheel builder but passes here.  @jreback 
I had an open review request on this PR. Can you please wait with merging in such cases until it has at least been discussed? @h-vetinari this was a straight revert and causing the CI to fail for several days. You should be familiar with how I work by now. We fix things step by step incrementally with orthogonal changes. you are welcome to propose changes if you want.