Optimize CRC intrinisics for targets lacking of CRC extension #27

Job	Run time
coding-style	21s
host-win-msvc	1m 8s
host-win (x86_64)	41s
host-arm (armv7, none, none, g++-10)	3m 29s
host-win (armv7)	39s
host-arm (armv7, none, none, clang++-11)	3m 39s
host-win (aarch64)	38s
host-x86 (x86_64, g++-10)	2m 14s
host-arm (aarch64, none, none, g++-10)	3m 53s
host-x86 (x86_64, clang++-11)	38s
host-arm (aarch64, none, none, clang++-11)	3m 33s
host-arm (aarch64, crypto+crc, none, g++-10)	2m 55s
host-arm (aarch64, crypto+crc, none, clang++-11)	3m 39s
host-arm (armv7, none, -mcpu=cortex-a32 -mfpu=neon-fp-armv8, g++-10)	3m 30s
host-arm (armv7, none, -mcpu=cortex-a32 -mfpu=neon-fp-armv8, clang++-11)	3m 36s
test-win-msvc	1m 0s
	35m 33s

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