ICU-22793 Clang-Tidy: google-readability-casting #2370

Job	Run time
clang-valgrind-test	9m 51s
clang-valgrind-intltest (utility)	6m 55s
clang-valgrind-intltest (normalize)	6m 1s
clang-valgrind-intltest (collator)	5m 7s
clang-valgrind-intltest (regex)	5m 2s
clang-valgrind-intltest (format)	16m 59s
clang-valgrind-intltest (translit)	5m 52s
clang-valgrind-intltest (rbbi)	6m 56s
clang-valgrind-intltest (rbnf)	6m 30s
clang-valgrind-intltest (rbnfrt)	6m 5s
clang-valgrind-intltest (icuserv)	5m 7s
clang-valgrind-intltest (idna)	4m 57s
clang-valgrind-intltest (convert)	6m 48s
clang-valgrind-intltest (rbnfp)	4m 51s
clang-valgrind-intltest (csdet)	5m 17s
clang-valgrind-intltest (spoof)	5m 17s
clang-valgrind-intltest (bidi)	5m 21s
	1h 52m 56s

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