[telemetry] Sort imports in Telemetry and its dependents.

tools/perf/measurements/v8_detached_context_age_in_gc_unittest.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-from measurements import v8_detached_context_age_in_gc
 from telemetry.core import wpr_modes
+from telemetry.page import page as page_module
 from telemetry.page import page_test
-from telemetry.page import page as page_module
 from telemetry.results import page_test_results
 from telemetry.unittest_util import options_for_unittests
 from telemetry.unittest_util import page_test_test_case
 from telemetry.value import skip
 
+from measurements import v8_detached_context_age_in_gc
+
 
 class FakePage(object):
   def __init__(self, url):
     self.url = url
     self.is_file = url.startswith('file://')
 
 
 class FakeTab(object):
   def __init__(self, histograms):
     self.histograms = histograms
@@ skipping 65 matching lines @@
   def testWithSimplePage(self):
     page_set = self.CreateEmptyPageSet()
     page = SimplePage(page_set)
     page_set.AddUserStory(page)
     metric = v8_detached_context_age_in_gc.V8DetachedContextAgeInGC()
     results = self.RunMeasurement(metric, page_set, options=self._options)
     self.assertEquals(0, len(results.failures))
     actual = _ActualValues(results)['V8_DetachedContextAgeInGC']
     self.assertLessEqual(0, actual.value)
     self.assertEqual('garbage_collections', actual.units)