[GR-62372] Use the canonicalized name when retrieving TimeZone object.

PullRequest: js/3427

Author: iamstolis

graal-js/src/com.oracle.truffle.js.test/js/GR-62372.js

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.
+ */
+
+/**
+ * Regression test of the handling of a non-canonicalized zone-rules-based time zone.
+ * 
+ * @option js.zone-rules-based-time-zones
+ */
+
+load("assert.js");
+
+assertSame('EST', new Intl.DateTimeFormat([], { timeZone: 'EST' }).resolvedOptions().timeZone);

graal-js/src/com.oracle.truffle.js/src/com/oracle/truffle/js/nodes/intl/InitializeDateTimeFormatNode.java

@@ -282,7 +282,7 @@ private Pair<TimeZone, String> parseAndGetICUTimeZone(String name) {
                 throw Errors.createRangeErrorInvalidTimeZone(name);
             }
             tzId = pair.getFirst();
-            timeZone = IntlUtil.getICUTimeZone(tzId, context);
+            timeZone = IntlUtil.getICUTimeZone(pair.getSecond(), context);
         } else {
             timeZone = IntlUtil.getICUTimeZoneForOffset(tzId);
         }