Update GrVkRenderTarget to store both stencil & non-stencil render passes (for real)

This is to allow reuse of a Vk render target in both stencil and non-stencil use cases.

Change-Id: Ic35285e66c173db7c0bf6440d95549cf1371ed43
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/291077
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
25 files changed