This is a reland of a36e089065
This is only active when Metal is enabled.
Original change's description:
> Added AutoreleasePool for managing pool memory in testing apps.
>
> This is only active on MacOS and iOS -- on other platforms it
> will do nothing as they have no need for autorelease pools.
>
> Bug: skia:8243
> Change-Id: Ib74968dab6e3455a72e726429832101d0d410076
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/217126
> Commit-Queue: Jim Van Verth <jvanverth@google.com>
> Reviewed-by: Brian Osman <brianosman@google.com>
Bug: skia:8243
Change-Id: I743a3dcc93b46387a6a330e855c2e8810b482544
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/217379
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>