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/ecma/operations/ecma-function-object.c

@@ -121,6 +121,8 @@ ecma_object_t *
 ecma_op_create_function_object (ecma_object_t *scope_p, /**< function's scope */
                                 const ecma_compiled_code_t *bytecode_data_p) /**< byte-code array */
 {
+  JERRY_ASSERT (ecma_is_lexical_environment (scope_p));
+
   /* 1., 4., 13. */
   ecma_object_t *prototype_obj_p = ecma_builtin_get (ECMA_BUILTIN_ID_FUNCTION_PROTOTYPE);