gh-116397: Move the _PyGC_ClearAllFreeLists to the safe point

[corona10]

• Issue: _PyGC_ClearAllFreeLists called while other threads may be running #116397

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @corona10 for commit 9ec369f 🤖

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

[colesbury]

We should run the refleak buildbots on this PR. If the refleak tracking or allocated blocks tests are a problem, we may also want to clear the current thread's free-list again after the GC (i.e., where we previously were calling _PyGC_ClearAllFreeLists()). That should be safe and I expect will fix the tests.

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @corona10 for commit 371b979 🤖

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

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @corona10 for commit be83eeb 🤖

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