#643 Make CRC hardware acceleration optional

[Daniel Rubery]

It's slightly helpful for fuzzers to be able to disable CRC checks. This was previously done in Chromium by overriding g_CrcTable, but hardware-accelerated CRC breaks that. The attached patch would allow Chromium to define Z7_NO_CRC_HW_FORCE to instead leave hardware acceleration dependent on g_Crc_Algo.

This was also filed as https://github.com/ip7z/7zip/pull/128, since I'm not sure what the official policy is for upstreaming changes.