Optimize CRC intrinisics for targets lacking of CRC extension #49

Job	Run time
host-win (x86_64)	47s
coding-style	9s
host-win-msvc	1m 44s
host-win (armv7)	43s
host-arm (armv7, none, none, g++-10)	3m 12s
host-arm (armv7, none, none, clang++-11)	3m 22s
host-win (aarch64)	50s
host-arm (aarch64, none, none, g++-10)	2m 49s
host-x86 (x86_64, g++-10)	2m 1s
host-arm (aarch64, none, none, clang++-11)	3m 24s
host-x86 (x86_64, clang++-11)	21s
host-arm (aarch64, crypto+crc, none, g++-10)	2m 44s
host-arm (aarch64, crypto+crc, none, clang++-11)	3m 51s
host-arm (armv7, none, -mcpu=cortex-a32 -mfpu=neon-fp-armv8, g++-10)	3m 18s
host-arm (armv7, none, -mcpu=cortex-a32 -mfpu=neon-fp-armv8, clang++-11)	3m 18s
test-win-msvc	1m 4s
	33m 37s

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