Add Timeout expectation for inspector/split-view.html

BUG=366185
TBR=pfeldman
NOTRY=true

Review URL: https://codereview.chromium.org/249343003

git-svn-id: svn://svn.chromium.org/blink/trunk@172397 bbb929c8-8fbe-4397-9dbb-9b2b20218538