legacy tests: migrate test4

src/nvim/testdir/test4.in

@@ -1,31 +0,0 @@
-Test for autocommand that changes current buffer on BufEnter event.
-Check if modelines are interpreted for the correct buffer.
-
-STARTTEST
-:so small.vim
-:set nocompatible viminfo+=nviminfo
-:au BufEnter Xxx brew
-/start of
-:.,/end of/w! Xxx   " write test file Xxx
-:set ai modeline modelines=3
-:sp Xxx             " split to Xxx, autocmd will do :brew
-G?this is a
-othis should be auto-indented
-:                   " Append text with autoindent to this file
-:au! BufEnter Xxx
-:buf Xxx            " go to Xxx, no autocmd anymore
-G?this is a
-othis should be in column 1:wq " append text without autoindent to Xxx
-G:r Xxx             " include Xxx in the current file
-:?startstart?,$w! test.out
-:qa!
-ENDTEST
-
-startstart
-start of test file Xxx
-vim: set noai :
-	this is a test
-	this is a test
-	this is a test
-	this is a test
-end of test file Xxx

src/nvim/testdir/test4.ok

@@ -1,17 +0,0 @@
-startstart
-start of test file Xxx
-vim: set noai :
-	this is a test
-	this is a test
-	this is a test
-	this is a test
-	this should be auto-indented
-end of test file Xxx
-start of test file Xxx
-vim: set noai :
-	this is a test
-	this is a test
-	this is a test
-	this is a test
-this should be in column 1
-end of test file Xxx