ICU-22568 return TimeZomeFormat::createInstance for bogus locale #1176

Job	Run time
clang-valgrind-intltest (utility)	8m 42s
clang-valgrind-test	9m 59s
clang-valgrind-intltest (normalize)	6m 14s
clang-valgrind-intltest (collator)	5m 13s
clang-valgrind-intltest (regex)	5m 29s
clang-valgrind-intltest (format)	15m 39s
clang-valgrind-intltest (translit)	5m 55s
clang-valgrind-intltest (rbbi)	7m 8s
clang-valgrind-intltest (rbnf)	7m 54s
clang-valgrind-intltest (rbnfrt)	6m 0s
clang-valgrind-intltest (icuserv)	5m 6s
clang-valgrind-intltest (idna)	5m 7s
clang-valgrind-intltest (convert)	6m 31s
clang-valgrind-intltest (rbnfp)	5m 6s
clang-valgrind-intltest (csdet)	5m 3s
clang-valgrind-intltest (spoof)	5m 5s
clang-valgrind-intltest (bidi)	9m 14s
	1h 59m 25s

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