Split test_ops_compat into targeted tests
This and a couple other test-organizing PRs are being split off of a WIP branch to fix division-by-zero consistency.

- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19334?src=pr&el=h1) Report
> Merging [#19334](https://codecov.io/gh/pandas-dev/pandas/pull/19334?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/6ba65ca8a69560d526762bdbded64b3139f66d7a?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/19334/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/19334?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #19334   +/-   ##
=======================================
  Coverage   91.57%   91.57%           
=======================================
  Files         150      150           
  Lines       48700    48700           
=======================================
  Hits        44595    44595           
  Misses       4105     4105
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.94% <ø> (ø)` | :arrow_up: |
| #single | `41.72% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19334?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/19334?src=pr&el=footer). Last update [6ba65ca...f4e8aba](https://codecov.io/gh/pandas-dev/pandas/pull/19334?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 thanks!