Don't rely on string CoreExtensions in StringInquirer since it is sometimes...

Don't rely on string CoreExtensions in StringInquirer since it is sometimes expected to work before the core extension are loaded
Signed-off-by: NDavid Heinemeier Hansson <david@loudthinking.com>

activesupport/lib/active_support/string_inquirer.rb

@@ -11,7 +11,7 @@ module ActiveSupport
   #
   class StringInquirer < String
     def method_missing(method_name, *arguments)
-      if method_name.to_s.ends_with?("?")
+      if method_name.to_s[-1,1] == "?"
         self == method_name.to_s[0..-2]
       else
         super