[issue17338] Add length_hint parameter to list, dict, set constructors to allow efficient presizing

[Giampaolo Rodola']

Changes by Giampaolo Rodola' <g.rodola at gmail.com>:


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nosy: +giampaolo.rodola

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue17338>
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