ICU-22991 Reduce Calendar object size #3325

Job	Run time
clang-valgrind-test	10m 33s
clang-valgrind-intltest (utility)	7m 4s
clang-valgrind-intltest (normalize)	6m 41s
clang-valgrind-intltest (collator)	5m 18s
clang-valgrind-intltest (regex)	5m 37s
clang-valgrind-intltest (format)	17m 6s
clang-valgrind-intltest (translit)	6m 18s
clang-valgrind-intltest (rbbi)	8m 9s
clang-valgrind-intltest (rbnf)	8m 15s
clang-valgrind-intltest (rbnfrt)	6m 34s
clang-valgrind-intltest (icuserv)	5m 31s
clang-valgrind-intltest (idna)	5m 43s
clang-valgrind-intltest (convert)	7m 10s
clang-valgrind-intltest (rbnfp)	6m 11s
clang-valgrind-intltest (csdet)	5m 30s
clang-valgrind-intltest (spoof)	5m 24s
clang-valgrind-intltest (bidi)	5m 30s
	2h 2m 34s

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