Vulkan: Use the correct context in ImageVk::orphan. The context used for Image creation was being used during orphaning. This causes problems when the image is created with an external source or when different contexts are used between creation and orphaning. BUG=angleproject:3722 Change-Id: Iee4abd2116c3410efd8fb35722cc956cc6d8a3fa Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1709753 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>