cmd: Turn off echo, add visual separator between testcases.

programs/cmd/tests/test_builtins.cmd

-rem Tests for echo
+echo Tests for cmd's builtin commands
+@echo off
 
+echo ------------ Testing 'echo' --------------
 echo word
 echo 'singlequotedword'
 echo "doublequotedword"

programs/cmd/tests/test_builtins.cmd.out

 
-@pwd@>rem Tests for echo@todo_space@
-
-@pwd@>echo word@todo_space@
+@pwd@>echo Tests for cmd's builtin commands@todo_space@
+Tests for cmd's builtin commands
+------------ Testing 'echo' --------------
 word
-
-@pwd@>echo 'singlequotedword'@todo_space@
 'singlequotedword'
-
-@pwd@>echo "doublequotedword"@todo_space@
 "doublequotedword"
 at-echoed-word
-
-@pwd@>echo "/?"@todo_space@
 "/?"
 
-@pwd@>echo.
-
-
-@pwd@>echo .@todo_space@
 .