patch 9.0.0187: command line height changes when maximizing window height

Problem:    Command line height changes when maximizing window height.
Solution:   Do not change the command line height. (closes #10885)

src/testdir/test_window_cmd.vim

@@ -38,6 +38,26 @@ func Test_window_cmd_cmdwin_with_vsp()
   set ls&vim
 endfunc
 
+func Test_cmdheight_not_changed()
+  set cmdheight=2
+  set winminheight=0
+  augroup Maximize
+    autocmd WinEnter * wincmd _
+  augroup END
+  split
+  tabnew
+  tabfirst
+  call assert_equal(2, &cmdheight)
+
+  tabonly!
+  only
+  set winminwidth& cmdheight&
+  augroup Maximize
+    au!
+  augroup END
+  augroup! Maximize
+endfunc
+
 " Test for jumping to windows
 func Test_window_jump()
   new

src/version.c

@@ -735,6 +735,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    187,
 /**/
     186,
 /**/

src/window.c

@@ -5666,8 +5666,6 @@ win_setheight_win(int height, win_T *win)
     if (full_screen && msg_scrolled == 0 && row < cmdline_row)
 	screen_fill(row, cmdline_row, 0, (int)Columns, ' ', ' ', 0);
     cmdline_row = row;
-    p_ch = MAX(Rows - cmdline_row, 0);
-    curtab->tp_ch_used = p_ch;
     msg_row = row;
     msg_col = 0;