Telemetry: Exclude techcrunch.com from power.top_25

Exclude techcrunch.com from power.top_25 . It is not suitable for this
benchmark because it does not consistently become quiescent within
60 seconds.

BUG=489214
CQ_EXTRA_TRYBOTS=tryserver.chromium.perf:linux_perf_bisect;tryserver.chromium.perf:mac_perf_bisect;tryserver.chromium.perf:win_perf_bisect;tryserver.chromium.perf:android_nexus5_perf_bisect

Review URL: https://codereview.chromium.org/1138243003

Cr-Commit-Position: refs/heads/master@{#330568}

tools/perf/benchmarks/power.py

@@ -52,7 +52,7 @@ class PowerTop10(benchmark.Benchmark):
     return 'power.top_10'
 
 
-@benchmark.Disabled()  # crbug.com/489214
+@benchmark.Enabled('mac')
 class PowerTop25(benchmark.Benchmark):
   """Top 25 quiescent power test."""
   test = power.QuiescentPower
@@ -60,3 +60,12 @@ class PowerTop25(benchmark.Benchmark):
   @classmethod
   def Name(cls):
     return 'power.top_25'
+
+  def CreateUserStorySet(self, _):
+    # Exclude techcrunch.com. It is not suitable for this benchmark because it
+    # does not consistently become quiescent within 60 seconds.
+    user_stories = self.page_set()
+    found = next((x for x in user_stories if 'techcrunch.com' in x.url), None)
+    if found:
+      user_stories.RemoveUserStory(found)
+    return user_stories