Fix incorrect feature guard for class support (#2992)

In `ecma-helpers.c` there was an incorrect macro guard which
tested the `JERRY_ES2015` feature but the `JERRY_ES2015_CLASS`
feature should be tested instead.

Profile options for testing:
* JERRY_ES2015=0
* JERRY_ES2015_CLASS=1
* JERRY_ES2015_OBJECT_INITIALIZER=1

JerryScript-DCO-1.0-Signed-off-by: Peter Gal pgal.u-szeged@partner.samsung.com

Author: galpeter

jerry-core/ecma/base/ecma-helpers.c

@@ -361,12 +361,12 @@ ecma_get_lex_env_binding_object (const ecma_object_t *object_p) /**< object-boun
 {
   JERRY_ASSERT (object_p != NULL);
   JERRY_ASSERT (ecma_is_lexical_environment (object_p));
-#if ENABLED (JERRY_ES2015)
+#if ENABLED (JERRY_ES2015_CLASS)
   JERRY_ASSERT (ecma_get_lex_env_type (object_p) == ECMA_LEXICAL_ENVIRONMENT_THIS_OBJECT_BOUND
                 || ecma_get_lex_env_type (object_p) == ECMA_LEXICAL_ENVIRONMENT_SUPER_OBJECT_BOUND);
-#else /* defined (JERRY_ES2015) || (JERRY_ES2015 == 0) */
+#else /* !ENABLED (JERRY_ES2015_CLASS) */
   JERRY_ASSERT (ecma_get_lex_env_type (object_p) == ECMA_LEXICAL_ENVIRONMENT_THIS_OBJECT_BOUND);
-#endif /* ENABLED (JERRY_ES2015) */
+#endif /* ENABLED (JERRY_ES2015_CLASS) */
 
   return ECMA_GET_NON_NULL_POINTER (ecma_object_t,
                                     object_p->property_list_or_bound_object_cp);