[Android] Revise SIGTERM and unknown test result handling.

build/android/pylib/base/base_test_result.py

 # Copyright (c) 2013 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.
 
 """Module containing base test results classes."""
 
 import threading
 
 
 class ResultType(object):
@@ skipping 143 matching lines @@
     return self.GetGtestForm()
 
   def AddResult(self, result):
     """Add |result| to the set.
 
     Args:
       result: An instance of BaseTestResult.
     """
     assert isinstance(result, BaseTestResult)
     with self._results_lock:
+      self._results.discard(result)
       self._results.add(result)
 
   def AddResults(self, results):
     """Add |results| to the set.
 
     Args:
       results: An iterable of BaseTestResult objects.
     """
     with self._results_lock:
       for t in results:
@@ skipping 45 matching lines @@
     return self._GetType(ResultType.UNKNOWN)
 
   def GetNotPass(self):
     """Get the set of all non-passed test results."""
     return self.GetAll() - self.GetPass()
 
   def DidRunPass(self):
     """Return whether the test run was successful."""
     return not self.GetNotPass() - self.GetSkip()