decompress_generic: Unroll loops a bit more
decompress_generic: Unroll loops a bit more

Generally we want our wildcopy loops to look like the
memcpy loops from our libc, but without the final byte copy checks.
We can unroll a bit to make long copies even faster.

The only catch is that this affects the value of FASTLOOP_SAFE_DISTANCE.

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso