[Telemetry] Explicitly define Name() method for all perf benchmarks

tools/perf/benchmarks/jetstream.py

Index: tools/perf/benchmarks/jetstream.py
diff --git a/tools/perf/benchmarks/jetstream.py b/tools/perf/benchmarks/jetstream.py
index 32b99f375300b417f515d424884a15d9cf9c0661..731d5125a7cb979ad9a1ae2954c7fd47f70a43a9 100644
--- a/tools/perf/benchmarks/jetstream.py
+++ b/tools/perf/benchmarks/jetstream.py
@@ -81,6 +81,10 @@ class _JetstreamMeasurement(page_test.PageTest):
 class Jetstream(benchmark.Benchmark):
   test = _JetstreamMeasurement
 
+  @classmethod
+  def Name(cls):
+    return 'jetstream'
+
   def CreatePageSet(self, options):
     ps = page_set.PageSet(
         archive_data_file='../page_sets/data/jetstream.json',