Add android load balancing shift

This CL saves ~50 minutes from the average Android Cycle times.

Note to perf sheriff, this may result a minor shift in the result for the android tests. It is unlikely since the hardware is typical.

R=sullivan@chromium.org
BUG=466101,471921

Review URL: https://codereview.chromium.org/1134633004

Cr-Commit-Position: refs/heads/master@{#329935}

tools/telemetry/telemetry/benchmark_runner.py

@@ -370,7 +370,8 @@ def _GetJsonBenchmarkList(possible_browser, possible_reference_browser,
     # for more details)
     hash_shift = {
       2 : 47,
-      5 : 56
+      5 : 56,
+      8 : 50
     }
     shift = hash_shift.get(num_shards, 0)
     base_name_hash = hashlib.sha1(base_name).hexdigest()