[dom-tests] Remove the unused selection variable from dom/common.js. (#1374)

It does not belong in the DOM test suite, and is not used there.

This also allows Servo to run tests that use it to completion.

View on GitHub: https://github.com/w3c/web-platform-tests/pull/1374

Received on Monday, 10 November 2014 10:45:01 UTC