Add tools/perf/contrib/cros_benchmarks/data/*.wprgo to .gitignore

Add tools/perf/contrib/cros_benchmarks/data/*.fetchts to .gitignore as well

Change-Id: Iac45358363d3c5e9f7399a035f7ab315006175c0
Reviewed-on: https://chromium-review.googlesource.com/1170159
Commit-Queue: Vovo Yang <vovoy@chromium.org>
Reviewed-by: Cheng-Yu Lee <cylee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582160}

tools/perf/contrib/cros_benchmarks/.gitignore

-*.wpr
+*.wprgo
+*.fetchts
 data/send_key_tab_switch