This avoids a SIGILL when running these tests on QEMU (which
defaults to a basic amd64 CPU without SSE4.2).
This commit also tests the table-based implementations in addition to
testing the hw-accelerated crc32 versions. Running these other versions
has exposed that the SSE4.2 version returns an incorrect value for the
last test: both software implementations and the ARM hardware-accelerated
version return 0x3207cc1c, but the SSE4.2 version returns 0xec638d62.