patch 8.2.1362: last entry of ":set term=xxx" overwritten by error message

Problem:    Last entry of ":set term=xxx" overwritten by error message when
            'cmdheight' is two or more. (Tony Mechelynck)
Solution:   Output extra line breaks.
diff --git a/src/testdir/test_termcodes.vim b/src/testdir/test_termcodes.vim
index 3012314..da2f066 100644
--- a/src/testdir/test_termcodes.vim
+++ b/src/testdir/test_termcodes.vim
@@ -7,6 +7,7 @@
 
 source shared.vim
 source mouse.vim
+source view_util.vim
 
 func Test_term_mouse_left_click()
   new
@@ -1893,6 +1894,17 @@
   set ttybuiltin
 endfunc
 
+func Test_list_builtin_terminals()
+  let buf = RunVimInTerminal('', #{rows: 14})
+  call term_sendkeys(buf, ":set cmdheight=3\<CR>")
+  call term_wait(buf, 100)
+  call term_sendkeys(buf, ":set term=xxx\<CR>")
+  call term_wait(buf, 100)
+  call assert_match('builtin_dumb', term_getline(buf, 11))
+  call assert_match('Not found in termcap', term_getline(buf, 12))
+  call StopVimInTerminal(buf)
+endfunc
+
 func GetEscCodeCSI27(key, modifier)
   let key = printf("%d", char2nr(a:key))
   let mod = printf("%d", a:modifier)