Enable forwarder2 for all our tests.

build/android/run_instrumentation_tests.py

Index: build/android/run_instrumentation_tests.py
diff --git a/build/android/run_instrumentation_tests.py b/build/android/run_instrumentation_tests.py
index 44c3e7aa3a2e0b514dd914588141431b2c140d44..09b2e25de9df1d234639ead6861b0e1ad8e865b5 100755
--- a/build/android/run_instrumentation_tests.py
+++ b/build/android/run_instrumentation_tests.py
@@ -12,10 +12,13 @@ import time
 
 from pylib import apk_info
 from pylib import buildbot_report
-from pylib import test_options_parser
+from pylib import constants
+from pylib import instrumentation_downstream_util
+from pylib import ports
 from pylib import run_java_tests
 from pylib import run_python_tests
 from pylib import run_tests_helper
+from pylib import test_options_parser
 from pylib.test_result import TestResults
 
 
@@ -53,6 +56,11 @@ def DispatchInstrumentationTests(options):
   Returns:
     An integer representing the number of failing tests.
   """
+  # Reset the test port allocation. It's important to do it before starting
+  # to dispatch any tests.
+  if not ports.ResetTestServerPortAllocation():
+    raise Exception('Failed to reset test server port.')
+
   start_date = int(time.time() * 1000)
   java_results = TestResults()
   python_results = TestResults()