patch 9.1.1253: abort when closing window with attached quickfix data

patch 9.1.1253: abort when closing window with attached quickfix data

Problem:  If win_close() is called with a window that has quickfix stack
          attached to it, the corresponding quickfix buffer will be
          closed and freed after the buffer was already closed. At that
          time curwin->w_buffer points to NULL, which the CHECK_CURBUF
          will catch and abort if ABORT_ON_ERROR is defined
Solution: in wipe_qf_buffer() temporarily point curwin->w_buffer back to
          curbuf, the window will be closed anyhow, so it shouldn't
          matter that curbuf->b_nwindows isn't incremented.

closes: #16993
closes: #16985

Co-authored-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>