use \xf0 instead of \xfd for valid first byte of a UTF-8 character.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@14121 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

bootstraptest/test_syntax.rb

@@ -626,5 +626,5 @@ assert_equal '2', %q{
 
 assert_match /illegal multibyte char/, %q{
   STDERR.reopen(STDOUT)
-  eval("\"\xfd".force_encoding("utf-8"))
+  eval("\"\xf0".force_encoding("utf-8"))
 }, '[ruby-dev:32429]'