Makes the Python tests more portable by calling standard functions to interpret the result of os.system(). This could fix the broken Python tests on some users' machines.

test/gtest_uninitialized_test.py

@@ -81,13 +81,7 @@ def TestExitCodeAndOutput(command):
   """Runs the given command and verifies its exit code and output."""
 
   # Verifies that 'command' exits with code 1.
-  if IS_WINDOWS:
-    # On Windows, os.system(command) returns the exit code of 'command'.
-    AssertEq(1, os.system(command))
-  else:
-    # On Unix-like system, os.system(command) returns 256 times the
-    # exit code of 'command'.
-    AssertEq(256, os.system(command))
+  AssertEq(1, gtest_test_utils.GetExitStatus(os.system(command)))
 
   output = GetOutput(command)
   Assert('InitGoogleTest' in output)