TST IntegerArray bounds error closing GH21796
- [x] closes #21796
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them


Thanks for the pr @TAJD! Think the test failure is because the test assumes int64, but on 32-bit builds or windows, the default integer size will be int32. So I'd suggest just not trying to match as completely or could use numpy's platform int Thanks @mzeitlin11 - hopefully by allowing 32 or 64 in the regex on the error message tests the required functionality. this is fine, though the message actually is *slightly* misleading, you are actually trying to cast to a nullable type, but the underlying casting is bubbled up here.

so merging this, but would be neat to look into having a slightly more informative message here.