[lldb] Use file-based synchronization in TestVSCode_attach

        shutil.copyfile(orig_program, program)

        shutil.copymode(orig_program, program)

        # Use a file as a synchronization point between test and inferior.

        pid_file_path = lldbutil.append_to_process_working_directory(self,

            "pid_file_%d" % (int(time.time())))

        def cleanup():

            if os.path.exists(program):

                os.unlink(program)

            self.run_platform_command("rm %s" % (pid_file_path))

        # Execute the cleanup function during test case tear down.

        self.addTearDownHook(cleanup)

        self.process = subprocess.Popen([program],

                                        stdin=subprocess.PIPE,

                                        stdout=subprocess.PIPE,

                                        stderr=subprocess.PIPE)

        # Wait for a bit to ensure the process is launched, but not for so long

        # that the process has already finished by the time we attach.

        time.sleep(3)

        popen = self.spawnSubprocess(program, [pid_file_path])

        self.addTearDownHook(self.cleanupSubprocesses)

        pid = lldbutil.wait_for_file_on_target(self, pid_file_path)

        self.attach(program=program)

        self.set_and_hit_breakpoint(continueToExit=True)

        # and use it for debugging

        attachCommands = [

            'target create -d "%s"' % (program),

            'process launch -- arg1'

            'process launch'

        ]

        initCommands = ['target list', 'platform list']

        preRunCommands = ['image list a.out', 'image dump sections a.out']

#include <stdio.h>

#include <unistd.h>

int main(int argc, char const *argv[])

{

int main(int argc, char const *argv[]) {

  lldb_enable_attach();

  if (argc >= 2) {

    // Create the synchronization token.

    FILE *f = fopen(argv[1], "wx");

    if (!f)

      return 1;

    fputs("\n", f);

    fflush(f);

    fclose(f);

  }

  printf("pid = %i\n", getpid());

  sleep(10);

  return 0; // breakpoint 1