TST: remove yielding tests from test_msgpacks.py
xref #15341 
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15427?src=pr&el=h1) Report
> Merging [#15427](https://codecov.io/gh/pandas-dev/pandas/pull/15427?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/9b5d8488e8184da0507c09482f23ebfff34ecc43?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.


```diff
@@           Coverage Diff           @@
##           master   #15427   +/-   ##
=======================================
  Coverage   90.37%   90.37%           
=======================================
  Files         135      135           
  Lines       49454    49454           
=======================================
  Hits        44694    44694           
  Misses       4760     4760
```



------

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> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15427?src=pr&el=footer). Last update [9b5d848...d6e1104](https://codecov.io/gh/pandas-dev/pandas/compare/9b5d8488e8184da0507c09482f23ebfff34ecc43...d6e110414feadcd8139a0597f185908875ce7bd2?src=pr&el=footer&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).