Message 262433 - Python tracker

Oooookay, it looks like all issues have been fixed. The optimization for compact keys has been implemented. I didn't see any crash on buildbots recently, test_tracemalloc pass on all platforms.

Nathaniel asked how domains will be "allocated" or "registered", but I suggest to discuss that in the issue #26530.

I close this issue that was much more difficult to implement than I expected...