Move a web test using Shadow DOM v0 out of virtual-stable

This patch is a preparation for Shadow DOM V0, Custom Element V0 (CEv0) and HTML Imports removal.
Intent to Deprecate and Remove: http://bit.ly/2RGHe3x
Though we soon make these APIs only available for test by turning the json5 feature flag
from status: "stable" to status: "test", there is browser tests/chrome internal components that
use them.

Since web_tests/compositing/* is virtual-tested turned on "--stable-release-mode" flag
 (https://cs.chromium.org/chromium/src/third_party/blink/web_tests/VirtualTestSuites?rcl=a8d05eee4d9d3d8e519c9edd2e0e2a6ca1d5173b&l=117)
and web_tests/compositing/gestures/gesture-tapHighlight-shadow-tree.html uses Shadow DOM v0,
removing the feature fails the virtual test.
This patch moves the test to fast/dom to avoid the stable-virtual-test.
(I tried to v1nize the test but "-webkit-tap-highlight-color" didn't style a slottee element.
We should fix it.)

Bug: 911943
Change-Id: I14b6ce5d70d98e8f4c02cb9d96170657fec5ecb6
Reviewed-on: https://chromium-review.googlesource.com/c/1405126
Reviewed-by: Hayato Ito <hayato@chromium.org>
Commit-Queue: Yoichi Osato <yoichio@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622774}
4 files changed