DevTools: Drop CSS Selector Profiler

It is of little use now, and its removal will help get rid of StyleRuleBase::m_sourceLine.

R=eseidel@chromium.org
BUG=265486

Review URL: https://codereview.chromium.org/21049007

git-svn-id: svn://svn.chromium.org/blink/trunk@155166 bbb929c8-8fbe-4397-9dbb-9b2b20218538