ICU-22559 Hardcode the macroregions and add a debug assertion #1143

Job	Run time
clang-valgrind-test	12m 50s
clang-valgrind-intltest (utility)	8m 35s
clang-valgrind-intltest (normalize)	7m 40s
clang-valgrind-intltest (collator)	9m 18s
clang-valgrind-intltest (regex)	9m 8s
clang-valgrind-intltest (format)	22m 6s
clang-valgrind-intltest (translit)	9m 5s
clang-valgrind-intltest (rbbi)	11m 15s
clang-valgrind-intltest (rbnf)	8m 58s
clang-valgrind-intltest (rbnfrt)	9m 27s
clang-valgrind-intltest (icuserv)	8m 49s
clang-valgrind-intltest (idna)	9m 2s
clang-valgrind-intltest (convert)	9m 26s
clang-valgrind-intltest (rbnfp)	5m 49s
clang-valgrind-intltest (csdet)	7m 29s
clang-valgrind-intltest (spoof)	8m 52s
clang-valgrind-intltest (bidi)	6m 23s
	2h 44m 12s

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