Backport 8330802: Desugar switch in Locale::createLocale

src/java.base/share/classes/java/util/Locale.java

@@ -927,11 +927,11 @@ static Locale getInstance(BaseLocale baseloc, LocaleExtensions extensions) {
 
     private static final ReferencedKeyMap<Object, Locale> LOCALE_CACHE = ReferencedKeyMap.create(true, ConcurrentHashMap::new);
     private static Locale createLocale(Object key) {
-        return switch (key) {
-            case BaseLocale base -> new Locale(base, null);
-            case LocaleKey lk -> new Locale(lk.base, lk.exts);
-            default -> throw new InternalError("should not happen");
-        };
+        if (key instanceof BaseLocale base) {
+            return new Locale(base, null);
+        }
+        LocaleKey lk = (LocaleKey)key;
+        return new Locale(lk.base, lk.exts);
     }
 
     private static final class LocaleKey {