[LayoutNG] flag-specific rebaselines for text-only failuers

Images match, and text dumps match after normalizations:
  svg/as-border-image/svg-as-border-image-2.html
  svg/as-border-image/svg-as-border-image.html

Images match, and text dump diffs are intentional:
  fast/box-shadow/basic-shadows.html
  fast/forms/form-hides-table.html
  fast/forms/search/search-appearance-basic.html
  fast/forms/select/select-initial-position.html
  fast/frames/iframe-with-frameborder.html
  fast/parser/001.html

From manual review of build 8093.

TBR=eae@chromium.org, mstensho@chromium.org
NOTRY=true

Bug: 591099
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: If0df956ec2508d4c710247c8caaff20e898a86bf
Reviewed-on: https://chromium-review.googlesource.com/1143045
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576379}
9 files changed