DM: more invariants

DM: more invariants

  - add ViaPicture
  - run ViaPicture on most bots
  - run ViaSecondPicture (tests SkPictureRecorder reuse) and ViaTwice (tests caching) on some bots
  - extend ViaSerialization reference checking to ViaPicture, ViaSecondPicture,
    ViaSingletonPictures, and ViaTwice
  - suppress current reference check failures with --blacklist

I'm open to following up on changing how those suppressions work.

Passing --nocheck turns off these invariant checks, letting us debug failures with normal image diff tools.

CQ_EXTRA_TRYBOTS=client.skia:Test-Win8-MSVC-ShuttleB-CPU-AVX2-x86_64-Release-Trybot

BUG=skia:4769
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1569823006

Review URL: https://codereview.chromium.org/1569823006