DevTools: Remove orphaned CSS rules [C]

Source/devtools/front_end/inspectorStyle.css:422 toolbar-item
https://codereview.chromium.org/46773004

Source/devtools/front_end/inspectorStyle.css:1324 webkit-line-gutter-backdrop
https://bugs.webkit.org/show_bug.cgi?id=34263

Source/devtools/front_end/networkLogView.css:573 filtered-out
https://codereview.chromium.org/364603002

Source/devtools/front_end/networkLogView.css:365 waiting-right
https://bugs.webkit.org/show_bug.cgi?id=45657

Source/devtools/front_end/resourcesPanel.css:322 database-table-storage-tree-item
https://bugs.webkit.org/show_bug.cgi?id=47988

Source/devtools/front_end/responsiveDesignView.css:425 media-inspector-min-width-label-container
https://codereview.chromium.org/346843005

BUG=
NOTRY=true

Review URL: https://codereview.chromium.org/433903007

git-svn-id: svn://svn.chromium.org/blink/trunk@179407 bbb929c8-8fbe-4397-9dbb-9b2b20218538