Probably due to compiler optimizations the Go code is now faster than the SSSE3/AVX/AVX2 code:

```
BenchmarkHash/GEN_/8Bytes-32    	 6486468	       184 ns/op	  43.46 MB/s
BenchmarkHash/GEN_/1K-32        	  545470	      2172 ns/op	 471.36 MB/s
BenchmarkHash/GEN_/8K-32        	   74073	     16106 ns/op	 508.64 MB/s
BenchmarkHash/GEN_/1M-32        	     584	   2034247 ns/op	 515.46 MB/s
BenchmarkHash/GEN_/5M-32        	     100	  10190003 ns/op	 514.51 MB/s
BenchmarkHash/GEN_/10M-32       	      56	  20357139 ns/op	 515.09 MB/s

BenchmarkHash/AVX2/8Bytes-32    	 5263258	       226 ns/op	  35.44 MB/s
BenchmarkHash/AVX2/1K-32        	  444441	      2633 ns/op	 388.98 MB/s
BenchmarkHash/AVX2/8K-32        	   61855	     19513 ns/op	 419.81 MB/s
BenchmarkHash/AVX2/1M-32        	     487	   2462013 ns/op	 425.90 MB/s
BenchmarkHash/AVX2/5M-32        	      91	  12384626 ns/op	 423.34 MB/s
BenchmarkHash/AVX2/10M-32       	      44	  26636364 ns/op	 393.66 MB/s

BenchmarkHash/AVX_/8Bytes-32    	 6349206	       188 ns/op	  42.54 MB/s
BenchmarkHash/AVX_/1K-32        	  461538	      2620 ns/op	 390.91 MB/s
BenchmarkHash/AVX_/8K-32        	   61224	     19567 ns/op	 418.65 MB/s
BenchmarkHash/AVX_/1M-32        	     484	   2473140 ns/op	 423.99 MB/s
BenchmarkHash/AVX_/5M-32        	      99	  12505052 ns/op	 419.26 MB/s
BenchmarkHash/AVX_/10M-32       	      46	  24869557 ns/op	 421.63 MB/s

BenchmarkHash/SSSE/8Bytes-32    	 6282679	       192 ns/op	  41.71 MB/s
BenchmarkHash/SSSE/1K-32        	  461614	      2628 ns/op	 389.69 MB/s
BenchmarkHash/SSSE/8K-32        	   60913	     19651 ns/op	 416.88 MB/s
BenchmarkHash/SSSE/1M-32        	     481	   2488563 ns/op	 421.36 MB/s
BenchmarkHash/SSSE/5M-32        	      91	  12516477 ns/op	 418.88 MB/s
BenchmarkHash/SSSE/10M-32       	      46	  24869561 ns/op	 421.63 MB/s
```