Revert of [Telemetry] Disable flaky smoothness.top_25 and testRepaint

tools/perf/benchmarks/scheduler.py

 # Copyright 2014 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 telemetry import test
 from measurements import smoothness
 import page_sets
 
 
-@test.Disabled('linux')  # crbug.com/368767
 class SchedulerToughSchedulingCases(test.Test):
   """Measures rendering statistics while interacting with pages that have
   challenging scheduling properties.
 
   https://docs.google.com/a/chromium.org/document/d/
       17yhE5Po9By0sCdM1yZT3LiUECaUr_94rQt9j-4tOQIM/view"""
   test = smoothness.Smoothness
   page_set = page_sets.ToughSchedulingCasesPageSet
 
 
 # Pepper plugin is not supported on android.
 @test.Disabled('android', 'win')  # crbug.com/384733
 class SchedulerToughPepperCases(test.Test):
   """Measures rendering statistics while interacting with pages that have
   pepper plugins"""
   test = smoothness.Smoothness
   page_set = page_sets.ToughPepperCasesPageSet
 
   def CustomizeBrowserOptions(self, options):
     # This is needed for testing pepper plugin.
     options.AppendExtraBrowserArgs('--enable-pepper-testing')