[issue35578] Add test for Argument Clinic converters

[Serhiy Storchaka]

Change by Serhiy Storchaka <storchaka+cpython at gmail.com>:


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keywords: +patch, patch
pull_requests: +10540, 10541
stage:  -> patch review

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue35578>
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