Fix file paths in dromaeo tests

Following https://codereview.chromium.org/24451002 the dromaeo tests
stopped running because:
1) The URL was of the form file:/// whereas a relative path is now
expected to be file://
2) navigate.py was stripping query and fragment off file URLs. These
are needed to control dromaeo.

BUG=308120
R=dtu@chromium.org

Review URL: https://codereview.chromium.org/27517004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228981 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228981