patch 8.1.0030: stoping Vim running in a terminal may not work

Problem:    Stoping Vim running in a terminal may not work.
Solution:   Instead of sending <Esc> send CTRL-O.

src/testdir/screendump.vim

@@ -81,7 +81,11 @@ endfunc
" Stop a Vim running in terminal buffer "buf".
func StopVimInTerminal(buf)
  call assert_equal("running", term_getstatus(a:buf))
  call term_sendkeys(a:buf, "\<Esc>:qa!\<cr>")

  " CTRL-O : works both in Normal mode and Insert mode to start a command line.
  " In Command-line it's inserted, the CTRL-U removes it again.
  call term_sendkeys(a:buf, "\<C-O>\<C-U>:qa!\<cr>")

  call WaitForAssert({-> assert_equal("finished", term_getstatus(a:buf))})
  only!
endfunc

src/testdir/test_prompt_buffer.vim

@@ -34,9 +34,12 @@ func Test_prompt_basic()
	\ 'func TimerFunc(text)',
	\ '  " Add the output above the current prompt.',
	\ '  call append(line("$") - 1, "Result: \"" . a:text . "\"")',
	\ '  " Reset &modified to allow the buffer to be closed.',
	\ '  set nomodified',
	\ 'endfunc',
	\ '',
	\ 'call setline(1, "other buffer")',
	\ 'set nomodified',
	\ 'new',
	\ 'set buftype=prompt',
	\ 'call prompt_setcallback(bufnr(""), function("TextEntered"))',

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =

static int included_patches[] =
{   /* Add new patch number below this line */
/**/
    30,
/**/
    29,
/**/