fix while.to_vool

sanitize normalizer on the way
- return ruby, let caller to_vool
- return single statement, not single? statements

test/ruby/test_while_statement.rb

@@ -19,7 +19,6 @@ module Ruby
       lst = compile( basic_while )
       assert_equal TrueConstant , lst.body.class
     end
-
     def reverse_while
       "true while(false)"
     end