Vulkan: Clean up rotation spec const update Update during makeCurrent was done by invalidating the program, and then at pipeline creation time the spec const was updated. This is changed so that makeCurrent updates the spec const directly, and avoid invalidating the pipeline. Also removes spec const usage calculation, as it's unused. Bug: angleproject:7369 Change-Id: I79444ce4173c4db9c6800fb02afd9e8447a25f82 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3963853 Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com>