[BlinGenPropertyTrees] Add virtual/not-blink-gen-property-trees

to ensure we don't regress --disable-blink-features=BlinkGenPropertyTrees
badly when experimenting BGPT.

Bug: 836884
Change-Id: Ie857f69e90bae243b55993fac58d04c478cb3b48
Reviewed-on: https://chromium-review.googlesource.com/c/1368144
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614789}
70 files changed