[Issue 20950] std.conv.text(int) shouldn't needlessly allocate

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20950

--- Comment #4 from Stanislav Blinov <stanislav.blinov at gmail.com> ---
https://issues.dlang.org/show_bug.cgi?id=17712

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