Made caption-side property independent.

Made caption-side property independent. Also updated
independent-inheritance-fast-path.html to include captionSide.

Tested using independent-inheritance-fast-path.html.

BUG=628043

Review-Url: https://codereview.chromium.org/2563443006
Cr-Commit-Position: refs/heads/master@{#437486}
2 files changed