Reland: Take 2: Force python test server output to be unbuffered, so it doesn't mix with gtest outpu

net/test/local_test_server_posix.cc

Index: net/test/local_test_server_posix.cc
diff --git a/net/test/local_test_server_posix.cc b/net/test/local_test_server_posix.cc
index 7afd422b94a6e1980a5f1e4019fbd0198ca58f8c..63aaa13e8b7eb8e7ce72fc66c668df30c32fc61e 100644
--- a/net/test/local_test_server_posix.cc
+++ b/net/test/local_test_server_posix.cc
@@ -99,7 +99,10 @@ bool LocalTestServer::LaunchPython(const FilePath& testserver_path) {
   // the same environment as the TestServer.
   VLOG(1) << "LaunchPython called with PYTHONPATH = " <<
           getenv(kPythonPathEnv);
-  CommandLine python_command(FilePath(FILE_PATH_LITERAL("python")));
+
+  CommandLine python_command(CommandLine::NO_PROGRAM);
+  if (!GetPythonRunTime(&python_command))
+    return false;
 
   python_command.AppendArgPath(testserver_path);
   if (!AddCommandLineArguments(&python_command))