[stdlib] Change Slice, Substring, CollectionOfOne and ReversedCollection to use _read/_modify#20965

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lorentey wants to merge 2 commits intoswiftlang:masterfrom

lorentey:more-reads

Commits on Nov 30, 2018

Change Slice and CollectionOfOne to use _read/_modify
airspeedswift
committed

Commits on Dec 3, 2018

[stdlib] Substring: Switch to _read in subscript accessors
lorentey
committed