patch 9.0.0326: some changes for cmdheight=0 are not needed

Problem:    Some changes for cmdheight=0 are not needed.
Solution:   Revert resize behavior if height is greater than the available
            space. (Shougo Matsushita, closes #11008)
diff --git a/src/window.c b/src/window.c
index 9c4a199..7ea7b5b 100644
--- a/src/window.c
+++ b/src/window.c
@@ -5694,10 +5694,8 @@
 	// topframe: can only change the command line height
 	if (height > ROWS_AVAIL)
 	    // If height is greater than the available space, try to create
-	    // space for the frame by reducing 'cmdheight' if possible, while
-	    // making sure `cmdheight` doesn't go below 1.
-	    height = MIN((p_ch > 0 ? ROWS_AVAIL + (p_ch - 1)
-							: ROWS_AVAIL), height);
+	    // space for the frame by reducing 'cmdheight' if possible.
+	    height = ROWS_AVAIL;
 	if (height > 0)
 	    frame_new_height(curfrp, height, FALSE, FALSE);
     }