message: [test] Fix 'argument must be str, not bytes' for Python 3.
  Use `sys.stdout.buffer` instead of `sys.stdout` in lldbpexpect.py.
diff: @@ -22,13 +22,13 @@ else:
  class PExpectTest(TestBase):
  NO_DEBUG_INFO_TESTCASE = True
  - PROMPT = str("(lldb) ")
  + PROMPT = "(lldb) "
  def expect_prompt(self):
  self.child.expect_exact(self.PROMPT)
  def launch(self, executable=None, timeout=30, dimensions=None):
  - logfile = sys.stdout if self.TraceOn() else None
  + logfile = sys.stdout.buffer if self.TraceOn() else None
  args = ['--no-lldbinit', '--no-use-colors']
  for cmd in self.setUpCommands():
  args += ['-O', cmd]
  