Migrate Buffer peek*Array methods to art/

This is the first half of part 2 from
https://b.corp.google.com/issues/176942060#comment4.
We will later use art internals to improve performance.

Test: m
Test: old (https://paste.googleplex.com/5268030335483904) vs new (https://paste.googleplex.com/6393930242326528) benchmark results
Bug: 176942060
Change-Id: Icf59511630b18c5ddbb743f0bfda80f88250b320
4 files changed