Fix mActiveImageShaderBits not updated in PPO's executable Allows the backend to rely on this bitset always being valid, instead of working around the bug. Bug: angleproject:5587 Change-Id: I25e1304c0e5e34b5fc1677a819315574603ed034 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2658885 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Tim Van Patten <timvp@google.com>