Vulkan: Fix mipmap generation and level redefinition When generating mipmaps, the non-base levels are redefined to be compatible. mRedefinedLevels was not updated to take this into account, resulting in invalid copies to the image. Additionally, noted a few spots where ImageDesc is used to respecify the image, but those are not up-to-date when the backend functions are called. Changed those to directly get the necessary information from the allocated image. Bug: chromium:1094644 Bug: chromium:1094599 Change-Id: I2afc9e5a53f24ef56836c5d7eec2e3e11df0ef61 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2267423 Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>