Add SegmentedList.shrink

I was exploring std.zig.Tokenizer and wanted to compare performance of
arrays, SegmentedList and ArrayList and needed SegmentedList.shrink
to make the comparison "fair".
81d9403dceWink Saville committed on 11/19/2018, 3:53:25 PM· committed by Andrew Kelleyparent4c0163b
1 file changedLine totals unavailable