Update invalidation commands to disable PLS Previously, commands that flush or invalidate tiled memory were specified to generate an error if issued while PLS was active. Remove all provisions around Flush(), Finish() and ClientWaitSync(), and add a test to ensure these commands have no effect on PLS. The reason we can make this change now is because we no longer support EXT_shader_pixel_local_storage, which previously prevented us from allowing these 3 commands. Update the invalidation commands to disable PLS instead. This is more in line with the general design pattern of PLS. Update the wording of the spec to reflect this better organization. Also clean up some legacy code that was no longer used. Bug: angleproject:40096838 Change-Id: I9687deaf17a583f8757ffcd050eda154b4e7a949 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6427324 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Chris Dalton <chris@rive.app> Reviewed-by: Kenneth Russell <kbr@chromium.org>