Move ProgramState::mImageBindings to ProgramExecutable The member ProgramState::mImageBindings is being moved to ProgramExecutable to allow ProgramExecutable::getImageBindings() to answer the query without relying on the Program[Pipeline]State. Bug: angleproject:4520 Test: Build/CQ Change-Id: Ia4934c8e57b5ba49b0a399dcad7c1b324c43385d Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2241750 Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Tim Van Patten <timvp@google.com>