ICU-22592 Rename source file that should not be directly compiled. #1271

Job	Run time
clang-valgrind-intltest (utility)	6m 51s
clang-valgrind-test	9m 55s
clang-valgrind-intltest (normalize)	6m 13s
clang-valgrind-intltest (collator)	5m 15s
clang-valgrind-intltest (regex)	5m 16s
clang-valgrind-intltest (format)	16m 43s
clang-valgrind-intltest (translit)	5m 30s
clang-valgrind-intltest (rbbi)	7m 12s
clang-valgrind-intltest (rbnf)	6m 22s
clang-valgrind-intltest (rbnfrt)	6m 4s
clang-valgrind-intltest (icuserv)	5m 8s
clang-valgrind-intltest (idna)	5m 4s
clang-valgrind-intltest (convert)	7m 9s
clang-valgrind-intltest (rbnfp)	5m 3s
clang-valgrind-intltest (csdet)	5m 17s
clang-valgrind-intltest (spoof)	5m 3s
clang-valgrind-intltest (bidi)	5m 20s
	1h 53m 25s

Provide feedback