Revise ES2015 feature guards (#3240)

All the basic language element guards are merged into JERRY_ES2015 macro guard.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

jerry-core/ecma/builtin-objects/ecma-builtin-internal-routines-template.inc.h

@@ -174,7 +174,7 @@ const ecma_builtin_property_descriptor_t PROPERTY_DESCRIPTOR_LIST_NAME[] =
     prop_attributes, \
     magic_string_id \
   },
-#if ENABLED (JERRY_ES2015_BUILTIN_SYMBOL)
+#if ENABLED (JERRY_ES2015)
 #define SYMBOL_VALUE(name, desc_string_id) \
   { \
     name, \
@@ -182,7 +182,7 @@ const ecma_builtin_property_descriptor_t PROPERTY_DESCRIPTOR_LIST_NAME[] =
     ECMA_PROPERTY_FIXED, \
     desc_string_id \
   },
-#endif /* ENABLED (JERRY_ES2015_BUILTIN_SYMBOL) */
+#endif /* ENABLED (JERRY_ES2015) */
 #define ACCESSOR_READ_WRITE(name, c_getter_name, c_setter_name, prop_attributes) \
   { \
     name, \