better explanations of ignored tests

packages/temporal-polyfill/scripts/test262-config/expected-failures-node-gte16.txt

@@ -1,7 +1,7 @@
-####################################################################################################
-# Intl
-####################################################################################################
-
 # NOT-IMPLEMENTED
-# We do not reject legacy ICU time zone IDs
+# For options passed to Intl.DateTimeFormat, we do not reject legacy ICU `timeZone`.
+#
+# Older versions of Node naturally fail on these IDs (ironically more compliant)
+# Newer versions of Node accept them (ironically less compliant)
+#
 intl402/DateTimeFormat/timezone-legacy-non-iana.js

packages/temporal-polyfill/scripts/test262-config/expected-failures-node-gte18.txt

@@ -1,5 +1,6 @@
-# Really picky about whitespace between characters
-# Nothing we can do about this since it relies on Intl.DateTimeFormat
+# Don't try to workaround buggy behavior in Node 18-20
+# Caused by https://bugs.chromium.org/p/chromium/issues/detail?id=1416538
+# Remove these lines after that bug is fixed.
 staging/Intl402/Temporal/old/date-time-format.js
 staging/Intl402/Temporal/old/datetime-toLocaleString.js
 staging/Intl402/Temporal/old/instant-toLocaleString.js

packages/temporal-polyfill/scripts/test262-config/expected-failures.txt

@@ -340,8 +340,8 @@ built-ins/Temporal/Duration/prototype/round/calendar-dateadd-called-with-plainda
 intl402/DateTimeFormat/timezone-case-insensitive.js
 intl402/DateTimeFormat/timezone-not-canonicalized.js
 
-# NOT-IMPLEMENTED
-# Intl.DateTimeFormat does not accept numeric-offset `timeZones`s and we are okay with that
+# These are caught by the default test glob, but are unrelated to Temporal.
+# They rely on Intl.DateTimeFormat supporting offset time zones.
 intl402/DateTimeFormat/prototype/format/offset-timezone-gmt-same.js
 intl402/DateTimeFormat/prototype/formatToParts/offset-timezone-correct.js
 intl402/DateTimeFormat/prototype/resolvedOptions/offset-timezone-basic.js