Add Module API to query for the number of methods

Author: shoumikhin

extension/module/module.h

@@ -138,6 +138,14 @@ class Module {
     return program_;
   }
 
+  /**
+   * Get the number of methods available in the loaded program.
+   *
+   * @returns A Result object containing either the number of methods available
+   *          or an error to indicate failure.
+   */
+  runtime::Result<size_t> num_methods();
+
   /**
    * Get a list of method names available in the loaded program.
    * Loads the program and method if needed.