Vulkan: readPixels improvement - use DynamicBuffer Reintroduce the change that was previously reverted here: https://chromium-review.googlesource.com/c/angle/angle/+/1064770 This includes a tentative fix the issue on Android that prompted the revert, we need to call invalidate on the mapped memory range before we read it on the host side. Bug: angleproject:2480 Change-Id: Id637bafa2845628ae38483c6fc8e6d7f26ad2d3e Reviewed-on: https://chromium-review.googlesource.com/1066229 Commit-Queue: Luc Ferron <lucferron@chromium.org> Reviewed-by: Yuly Novikov <ynovikov@chromium.org>