Add some copy support for vulkan msaa

This allows us to do copies from:
    msaa->msaa with same sample count
    msaa->no-msaa with a resolve

Still missing support for no-msaa to msaa which will require a copyAsDraw
which is currently stalled and fixing possible driver bugs.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2294533002

Review-Url: https://codereview.chromium.org/2294533002
9 files changed