[issue30040] new empty dict can be more small

[Inada Naoki]

Inada Naoki <songofacandy at gmail.com> added the comment:

I created two PRs.  PR 12307 just optimize inserting to empty dict.
PR 12308 has same optimization and removes shared empty key (ma_keys = NULL).

I confirmed PR 12307 is faster than before about `d = {}; d["a"]=None`.
I'll benchmark them later.

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue30040>
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