[misc] Combine SandboxAndroid and SandboxTizen

- sandbox allow-scripts has nothing to do with video element and
  video clip type; so use an image rather than video to avoid
  3rd party media resource
- format and rename other sandbox support files
- update test cases pass/fail criteria
[misc] Use 'Filler Text' rather than 'PASS'

The tests pass on Crosswalk Android
Merge pull request #766 from zqzhang/zqzhang/sandbox-usecase

[misc] Combine SandboxAndroid and SandboxTizen