Mark http/tests/inspector/elements/styles/selector-line-deprecated.html as non-flaky

BUG=331572
TBR=vsevik

Review URL: https://codereview.chromium.org/185383005

git-svn-id: svn://svn.chromium.org/blink/trunk@168301 bbb929c8-8fbe-4397-9dbb-9b2b20218538