Skip tests that depend on Intl.supportedValuesOf()

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UPSTREAM_COMMIT=3e5dce83966945c0410578f9d81b14cd98884b42

Author: ptomato

test/expected-failures-before-node18.txt

@@ -1,2 +1,4 @@
 # Intl.supportedValuesOf("timeZone") is only available starting in Node 18
 intl402/Temporal/TimeZone/supported-values-of.js
+intl402/Temporal/TimeZone/prototype/getNextTransition/transition-at-instant-boundaries.js
+intl402/Temporal/TimeZone/prototype/getPreviousTransition/transition-at-instant-boundaries.js