Revision 1696225

Following up on r1696222, implement polling on pipes on Windows.

Note that PeekNamedPipe() also works on unnamed pipes, such as those created
by apr to hook stdin and stdout of subprocesses.

* subversion/libsvn_subr/stream.c
  (data_available_handler_apr): Implement polling on pipes for Win32.

* subversion/tests/libsvn_ra/ra-test.c
  (test_funcs): Remove Windows specific XFail marking.