Remove TestRunner forwarding headers

These forwarding headers are no longer needed outside of Blink. This CL removes
them and updates all the code in Blink that was using them.

TBR=jochen
BUG=239545

Review URL: https://codereview.chromium.org/17804002

git-svn-id: svn://svn.chromium.org/blink/trunk@153046 bbb929c8-8fbe-4397-9dbb-9b2b20218538
This patch changes how the --timing flag works in run-webkit-tests.

--timing used to imply --verbose, and would log the per-test time along with the test name.

With this change, --timing no longer implies verbose. 

Instead, by default, it modifies the "one line summary" to containing timing information for the test run as a whole (total wall clock time, time spent running serially outside of the tests, and the relative speedup). 

If --verbose is also passed, we will log the per-test time as well.

Review URL: https://chromiumcodereview.appspot.com/17762005

git-svn-id: svn://svn.chromium.org/blink/trunk@153047 bbb929c8-8fbe-4397-9dbb-9b2b20218538