[telemetry] Followup fixes for http://crrev.com/228869

- Fix page cycler 404s. The problem was that the path methods stripped the trailing / from the url path, but the HTTP server expected it to be there.
- Update file:// URLs for new benchmarks.
- Properly handle param, query, and fragment strings.

BUG=308090
TEST=tools/perf/run_benchmark page_cycler.bloat; tools/perf/run_benchmark dromaeo.domcoreattr
R=tonyg@chromium.org

Review URL: https://codereview.chromium.org/27320003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229007 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229007