patch 8.0.0566: setting nocompatible for the tiny version moves the cursor

Problem:    Setting nocompatible for the tiny version moves the cursor.
Solution:   Use another trick to skip commands when the +eval feature is
            present. (Christian Brabandt, closes #1630)
diff --git a/runtime/defaults.vim b/runtime/defaults.vim
index f4d22bd..6fd43db 100644
--- a/runtime/defaults.vim
+++ b/runtime/defaults.vim
@@ -1,7 +1,7 @@
 " The default vimrc file.
 "
 " Maintainer:	Bram Moolenaar <Bram@vim.org>
-" Last change:	2017 Apr 01
+" Last change:	2017 Apr 12
 "
 " This is loaded if no vimrc file was found.
 " Except when Vim is run with "-u NONE" or "-C".
@@ -28,13 +28,9 @@
 
 " When the +eval feature is missing, the set command above will be skipped.
 " Use a trick to reset compatible only when the +eval feature is missing.
-if 1
-  nnoremap : :"
-endif
-silent normal :set nocompatible

-if 1
-  nunmap :
-endif
+silent! while 0
+  set nocompatible
+silent! endwhile
 
 " Allow backspacing over everything in insert mode.
 set backspace=indent,eol,start