Get storage buffers/images from ProgramExecutable Update StateCache::updateActiveShaderStorageBufferIndices() and StateCache::updateActiveImageUnitIndices to get the storage buffers and image bindings from the ProgramExecutable, respectively. This requires updating the ProgramPipeline's ProgramExecutable to build up its vector of buffers/images from each Program's ProgramExecutable. Bug: angleproject:4869 Test: VertexAttributeTestES31.UsePpoComputeShaderToUpdateVertexBuffer Test: SimpleStateChangeTestES31.InvalidateThenStorageWriteThenBlendPpo Change-Id: I68b7d23eedda910c3dcbf5f9c50b74b5e80134d8 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2327701 Commit-Queue: Tim Van Patten <timvp@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com>