Cache VkImageCreateFlags in ImageHelper. This allows texture target siblings to inherit a few VkImage create attributes thus avoiding image respecification in certain code paths. Bug: angleproject:2514 Bug: angleproject:5281 Test: PbufferTest.ClearAndBindTexImageSrgbSkipDecode*Vulkan Change-Id: Ic7397fabdce185264e06488355ca47f809338519 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2910473 Commit-Queue: Mohan Maiya <m.maiya@samsung.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
