Mark inspector/styles/multiple-imports-edit-crash.html as flaky

TBR=apavlov,dglazkov@chromium.org

Review URL: https://codereview.chromium.org/140993008

git-svn-id: svn://svn.chromium.org/blink/trunk@166127 bbb929c8-8fbe-4397-9dbb-9b2b20218538