Use the standard intrinsics for crc32c
Use the standard intrinsics for crc32c

Summary: This mass of conditions is completely pointless, because GCC has supported the standard intrinsics since at least 4.4.7, which is as far back as godbolt lets me test.

Reviewed By: yfeldblum

Differential Revision: D3373640

fbshipit-source-id: 619e971034db9249a9b312d18870bc7e4d579d50

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