DeviceMotion layout tests re arrangement

Inline the layout tests for device motion inside the .html
files, remove the need for a separate script-tests dir for the .js files.

Also in create-event.html check for bubbles, cancelable

Review URL: https://codereview.chromium.org/274633002

git-svn-id: svn://svn.chromium.org/blink/trunk@174016 bbb929c8-8fbe-4397-9dbb-9b2b20218538