ICU-22575 Change AvailableFormatsSink to allow locales to inherit ava… #1266

Job	Run time
clang-valgrind-intltest (utility)	6m 41s
clang-valgrind-intltest (normalize)	6m 30s
clang-valgrind-test	9m 54s
clang-valgrind-intltest (collator)	5m 7s
clang-valgrind-intltest (regex)	5m 2s
clang-valgrind-intltest (format)	16m 8s
clang-valgrind-intltest (translit)	5m 47s
clang-valgrind-intltest (rbbi)	6m 55s
clang-valgrind-intltest (rbnf)	6m 3s
clang-valgrind-intltest (rbnfrt)	6m 7s
clang-valgrind-intltest (icuserv)	5m 2s
clang-valgrind-intltest (idna)	4m 55s
clang-valgrind-intltest (convert)	6m 41s
clang-valgrind-intltest (rbnfp)	5m 5s
clang-valgrind-intltest (csdet)	5m 4s
clang-valgrind-intltest (spoof)	5m 6s
clang-valgrind-intltest (bidi)	5m 7s
	1h 51m 14s

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