[WIP] Update icu4c to version 71.1 #2182

Job	Run time
Flatpak	17m 25s
Macos (native_dyn)	24m 39s
Linux (native_static, focal)	22m 28s
Macos (native_static)	20m 44s
Linux (native_dyn, focal)	20m 43s
Macos (native_mixed)	19m 32s
Linux (native_mixed, focal)	16m 53s
Macos (iOS_arm64)	19m 47s
Linux (wasm, focal)	36m 48s
Macos (iOS_x86_64)	17m 34s
Linux (armv6_static, focal)	22m 13s
Macos (iOS_Mac_ABI)	17m 15s
Linux (armv6_dyn, focal)	20m 20s
Macos (macOS_arm64_static)	17m 44s
Linux (armv6_mixed, focal)	19m 34s
Macos (macOS_arm64_mixed)	18m 0s
Linux (armv8_static, focal)	20m 33s
Macos (macOS_x86_64)	19m 24s
Linux (armv8_dyn, focal)	20m 52s
Linux (armv8_mixed, focal)	16m 10s
Linux (aarch64_static, focal)	25m 1s
Linux (aarch64_dyn, focal)	25m 31s
Linux (aarch64_mixed, focal)	18m 38s
Linux (aarch64_musl_static, focal)	26m 8s
Linux (aarch64_musl_dyn, focal)	21m 2s
Linux (aarch64_musl_mixed, focal)	19m 22s
Linux (x86-64_musl_static, focal)	18m 43s
Linux (x86-64_musl_mixed, focal)	17m 40s
Linux (i586_static, focal)	14m 11s
Linux (i586_dyn, focal)	15m 30s
Linux (android_arm, focal)	1h 16m 29s
Linux (android_arm64, focal)	1h 15m 53s
Linux (android_x86, focal)	33m 18s
Linux (android_x86_64, focal)	35m 15s
Linux (native_mixed, bionic)	13m 26s
Linux (aarch64_mixed, bionic)	21m 5s
Linux (win32_static, f35)	13m 5s
Linux (win32_dyn, f35)	16m 48s
	14h 55m 43s

Provide feedback