gh-115999: remove redundant check in free-threading from _STORE_ATTR_WITH_HINT

[kumaraditya303]

• Issue: Make the specializing interpreter thread-safe in --disable-gil builds #115999

[colesbury]

You'll need to run make regen-cases

[kumaraditya303]

You'll need to run make regen-cases

Sorry, missed that, fixed now

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @colesbury for commit fb7523c 🤖

Results will be shown at:

https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F136249%2Fmerge

If you want to schedule another build, you need to add the 🔨 test-with-buildbots label again.

[colesbury]

For posterity: we don't need to re-check _PyObject_GetManagedDict() because LOCK_OBJECT never blocks. If LOCK_OBJECT() blocked (and detached the thread state), then we would have problems because the quiescent state might mean that a replaced manage dictionary could be freed.