ICU-22342 Rename fillBreak to fillBreaks #779

Job	Run time
clang-valgrind-test	13m 39s
clang-valgrind-intltest (utility)	8m 28s
clang-valgrind-intltest (normalize)	8m 9s
clang-valgrind-intltest (collator)	6m 14s
clang-valgrind-intltest (regex)	7m 40s
clang-valgrind-intltest (format)	25m 40s
clang-valgrind-intltest (translit)	9m 30s
clang-valgrind-intltest (rbbi)	11m 53s
clang-valgrind-intltest (rbnf)	9m 41s
clang-valgrind-intltest (rbnfrt)	7m 31s
clang-valgrind-intltest (icuserv)	6m 11s
clang-valgrind-intltest (idna)	7m 51s
clang-valgrind-intltest (convert)	8m 9s
clang-valgrind-intltest (rbnfp)	6m 37s
clang-valgrind-intltest (csdet)	6m 44s
clang-valgrind-intltest (spoof)	6m 31s
clang-valgrind-intltest (bidi)	6m 36s
	2h 37m 4s

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