Remove mProgramState from ProgramExecutable::isCompute() ProgramExecutable::isCompute() is being updated to no longer use mProgramState or mProgramPipelineState, as part of the effort to remove those members from ProgramExecutable. Functionally, things are the same for PPOs, but Programs are being updated to use the boolean ProgramExecutable::mIsCompute rather than checking the linked shader stages to determine draw vs compute. Slightly unrelated, but this CL also removes the unused function ProgramPipeline::hasImages() which was missed in one of the earlier CLs in this relation chain. Bug: angleproject:4520 Test: Build/CQ Change-Id: Ief28021310d6d0b1be5b7608a59deb87b0cf591d Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2243326 Commit-Queue: Tim Van Patten <timvp@google.com> Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org>