patch 8.2.4700: buffer remains active if WinClosed event throws an exception

Problem:    Buffer remains active if a WinClosed event throws an exception.
Solution:   Ignore aborting() when closing the buffer. (closes #10097)

src/testdir/test_autocmd.vim

@@ -348,6 +348,23 @@ func Test_WinClosed()
   unlet g:triggered
 endfunc
 
+func Test_WinClosed_throws()
+  vnew
+  let bnr = bufnr()
+  call assert_equal(1, bufloaded(bnr))
+  augroup test-WinClosed
+    autocmd WinClosed * throw 'foo'
+  augroup END
+  try
+    close
+  catch /.*/
+  endtry
+  call assert_equal(0, bufloaded(bnr))
+
+  autocmd! test-WinClosed
+  augroup! test-WinClosed
+endfunc
+
 func s:AddAnAutocmd()
   augroup vimBarTest
     au BufReadCmd * echo 'hello'

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4700,
 /**/
     4699,
 /**/

src/window.c

@@ -2493,7 +2493,7 @@ win_close_buffer(win_T *win, int action, int abort_if_last)
 
 	set_bufref(&bufref, curbuf);
 	win->w_closing = TRUE;
-	close_buffer(win, win->w_buffer, action, abort_if_last, FALSE);
+	close_buffer(win, win->w_buffer, action, abort_if_last, TRUE);
 	if (win_valid_any_tab(win))
 	    win->w_closing = FALSE;
 	// Make sure curbuf is valid. It can become invalid if 'bufhidden' is