Move "adb shell" over to getopt(3), and allow -tt on old devices.

From the bug:

  Say we run a new adb against an old device (like KitKat). Even with a new
  client ADB, in this configuration, "adb shell" will create a remove tty
  unconditionally. So if the user runs "adb shell -t -t", we shouldn't fail
  with a message about the remote device not supporting -tT options --- the
  user asked to create a tty unconditionally, and since we're going to create
  a tty unconditionally, we should just succeed. (That it's going to succeed
  due to protocol inadequacy instead of succeeding on purpose is irrelevant.)

  That adb fails in this case makes scripts more complicated, since they can't
  just pass "-t -t" unconditionally if they want a tty and to work on all
  device versions, even if the script requires a new-ish adb locally.

Bug: http://b/32216152
Bug: http://b/32219151
Test: test_device.py
Change-Id: I8ab7c8dfa212209a7ab43c1f0832eeac26d2e42f