STY: Check for pytest.raises without context
xref #24332 

First commit adds the script code for checking.  Remaining commits will fix any vestigial errors.
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25866?src=pr&el=h1) Report
> Merging [#25866](https://codecov.io/gh/pandas-dev/pandas/pull/25866?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/af6ccf64dab57cc90cce1582fea60fba13b2998a?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/25866/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25866?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #25866   +/-   ##
=======================================
  Coverage   91.48%   91.48%           
=======================================
  Files         175      175           
  Lines       52885    52885           
=======================================
  Hits        48380    48380           
  Misses       4505     4505
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.04% <ø> (ø)` | :arrow_up: |
| #single | `41.82% <ø> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25866?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/computation/pytables.py](https://codecov.io/gh/pandas-dev/pandas/pull/25866/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29tcHV0YXRpb24vcHl0YWJsZXMucHk=) | `90.24% <0%> (-0.31%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/25866/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `89.84% <0%> (+0.1%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25866?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/25866?src=pr&el=footer). Last update [af6ccf6...2733901](https://codecov.io/gh/pandas-dev/pandas/pull/25866?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @jreback : All is green now.  PTAL. thanks @gfyoung does this close the issue? @jreback : That number is a PR number (there was no issue for this).