Vulkan: Move cached samplers/images and has*() to ProgramExecutable The active samplers and images are being moved from Program into ProgramExecutable to unify interacting with them for Programs and ProgramPipelines Also, create some helper functions for gl::Program that ProgramExecutable can call to make it easier for ProgramPipeline to respond to similar queries for each of the Programs in the ProgramPipeline. Bug: angleproject:3570 Change-Id: I0b37f1a379e56b9659d82d92f6d7a546beee11cd Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2087648 Commit-Queue: Tim Van Patten <timvp@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org>