[LayoutNG] Remove duplicated flag-specfic baselines

This patch removes 84 flag-specific baselines that match to
their base expectations, probably due to multiple rebaselines.

The methodology relies on still experimental script, may cause
some flakiness or failures, but the effect is limited to
LayoutNG bots.

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

Bug: 591099
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Change-Id: Ie509850adf91829e2bf54384f673d185b68f3f5f
Reviewed-on: https://chromium-review.googlesource.com/1079108
Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562864}
84 files changed