dan sinclair 31e0850560 [ir] Convert instruction to a pointer
This CL updates the instruction class to be a `Castable` and allocated
from an Arena. Uses are updated to store the const pointer.

Bug: tint:1718
Change-Id: Ie0b8353cb0c6fe6e2ba6e01bcd45871891aef903
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/112045
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
2022-11-29 23:29:47 +00:00
..
2022-11-29 23:05:30 +00:00