libANGLE: Fix evaluating the sample count OpenGL deals with the maximum number of samples, but Vulkan provides a mask of supported sample counts, so extract and limit the maximum sample count accordingly. Bug: angleproject:7328 Change-Id: If4867b2a5104062ec863eb6eb1e0c8e78e7a9c00 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3652422 Commit-Queue: Gert Wollny <gert.wollny@collabora.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>