Accelerate byte lookup in string with `bytealg/indexbyte`
Accelerate byte lookup in string with `bytealg/indexbyte`

`bytealg/indexbyte` will use AVX or SSE instruction set, if possible,
which could accelerate `CopyStringIn` function by 28%.

In worst case(CPU doesn't support SSE), `bytealg/indexbyte`
will degenerate to traversal lookup. When dealing with
short strings, `bytealg/indexbyte` has the same performance level as
before.

Signed-off-by: Jianfeng Tan <5c9cbcdc6e9c03825adb30b0700a6649b56823d7@antfin.com>
Signed-off-by: Hang Su <496f08601a5122c69e4b401824de47c6b8d4f716@antfin.com>

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor