Vulkan: Remove the forceCPUPathForCubeMapCopy workaround This workaround has been disabled since https://chromium-review.googlesource.com/c/angle/angle/+/2594707 Bug: angleproject:2822 Bug: angleproject:3055 Change-Id: Ie9cc12c7616cd9e1801dbd92e21822c63f4d0bef Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3140214 Reviewed-by: Charlie Lao <cclao@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>