Bug 1863132 - Part 1: Update UNSUPPORTED_FEATURES in test262-update.py r=mgaudet

Differential Revision: https://phabricator.services.mozilla.com/D192785

js/src/tests/test262-update.py

@@ -28,6 +28,8 @@ UNSUPPORTED_FEATURES = set(
         "resizable-arraybuffer",  # Bug 1670026
         "regexp-duplicate-named-groups",  # Bug 1773135
         "json-parse-with-source",  # Bug 1658310
+        "import-attributes",  # Bug 1835669
+        "set-methods",  # Bug 1805038
     ]
 )
 FEATURE_CHECK_NEEDED = {