adb: SIGWINCH support for Windows

- Introduces unix_read_interruptible() which is like unix_read() except
  that it can return EINTR.

- The big idea is that the Windows ReadConsoleInput() API will return an
  event on window resize and then we return EINTR from
  unix_read_interruptible() just like Unix.

- Only handles horizontal resize since Windows doesn't seem to give an
  event for vertical resize when no special screen buffer is used. This
  should be sufficient for the primary use case of adb on Windows
  (people are not running vi in the first place).

Change-Id: Id8d1710b559834c8098f2d7fbecedf2d0ade4b88
Signed-off-by: Spencer Low <CompareAndSwap@gmail.com>