Fix named function expression creation. (#2634)

Create a local lexical environment with the name of the function. While
this is not too memory efficient, some corner cases requires its existence.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

jerry-core/parser/js/js-parser-internal.h

@@ -45,7 +45,6 @@ typedef enum
   PARSER_IS_FUNC_EXPRESSION = (1u << 3),      /**< a function expression is parsed */
   PARSER_IS_PROPERTY_GETTER = (1u << 4),      /**< a property getter function is parsed */
   PARSER_IS_PROPERTY_SETTER = (1u << 5),      /**< a property setter function is parsed */
-  PARSER_NAMED_FUNCTION_EXP = (1u << 6),      /**< a function expression has a name binding */
   PARSER_HAS_NON_STRICT_ARG = (1u << 7),      /**< the function has arguments which
                                                *   are not supported in strict mode */
   PARSER_ARGUMENTS_NEEDED = (1u << 8),        /**< arguments object must be created */