Revert "experimental/minimal_ios_mtl_skia_app"

This reverts commit c2dc9c864844a81736bff3d7a85570be0379706a.

Reason for revert: Build-Mac-Clang-arm64-Debug-iOS_Metal Build-Mac-Clang-arm64-Release-iOS_Metal broken:

    ninja: error: '../../../../../../skia/experimental/minimal_ios_mtl_skia_app/main.mm', needed by 'obj/experimental/minimal_ios_mtl_skia_app/gen/experimental/minimal_ios_mtl_skia_app/minimal_ios_mtl_skia_app.main.o', missing and no known rule to make it


Original change's description:
> experimental/minimal_ios_mtl_skia_app
> 
> Change-Id: Iec5b9d9b930cb8b2b97ce92c828ccba0a9e2a94d
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/238757
> Auto-Submit: Hal Canary <halcanary@google.com>
> Reviewed-by: Jim Van Verth <jvanverth@google.com>
> Commit-Queue: Jim Van Verth <jvanverth@google.com>

TBR=jvanverth@google.com,halcanary@google.com

Change-Id: I6a3c16131072019ba541ad573c95a8de4d2b5eef
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/239120
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
4 files changed